Part 8:Body of Secrets....Adrenaline

CHAPTER NINE 

ADRENALINE 

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In the penultimate days before the North Korean attack on the Pueblo, NSA's focus was on another troubled land severed along a degree of latitude: Vietnam. For the 2 million people packed as tightly as bullet casings into the twenty square miles of Saigon, the morning of January 22, 1968, began with a frenzy of activity. Emergency vehicles, rushing to a trio of separate terrorist incidents, performed pirouettes around fruit laden shoppers. Overhead, a swarm of helicopter gunships, like heavily armed locusts, searched back and forth across an open field for Communist guerrillas. In front of a cloud of hazy blue exhaust fumes, an American-made tank tore at a downtown pavement as the driver took a shortcut to a convoy of vehicles heading north. 

Amid the war, life went on as normal. At a restaurant near the Central Market, passersby inspected the barbecued chickens with their shiny lacquer like coatings, hanging from hooks in an open window. U.S. Air Force commandos in big hats and low-slung revolvers sipped bitter espresso at a stand-up counter, like gunslingers at a Wild West saloon. In the malodorous Ben Nghe Canal, gray wooden sampans pushed slowly past shacks perched on narrow, spindly legs. Policemen in tropical whites directed swirls of traffic at the broad circular intersections. 

In the far north on that Monday in January, at Firebase 861 near Khe Sanh, enemy soldiers lobbed mortar rounds and rifle grenades. American troops fought back through mailboxlike slits in the thick cement walls that protected them. Between explosions, a Marine battalion arrived to reinforce the garrison. Landing nearby were pallets containing 96,000 tons of ordnance. The day before, North Vietnamese Army forces had begun a siege of the hilltop outpost, and the United States was engaged in an all-out effort to save it. 

In charge of the American war was Army General William Westmoreland. On the afternoon of January 22, at his Saigon headquarters, his major worry was the powerful attack in the north on Khe Sanh. He compared it to the bloody assault on the French at Dien Bien Phu more than a dozen years earlier. But Westmoreland was intent on proving that massive firepower would allow the United States to succeed where the French had dismally failed. He believed that sometime prior to Tet— the Vietnamese New Year, nine days away—the guerrillas would launch a major attack in the far north, at Khe Sanh and some of the surrounding bases. Thus, he began focusing his men, munitions, and might in that high province. "I believe that the enemy will attempt a countrywide show of strength just prior to Tet," he cabled the Joint Chiefs of Staff in Washington, "with Khe Sanh being the main event." At the White House, President Johnson, following the action like a front-row fan at a championship boxing match, had a sand model of Khe Sanh built in the Situation Room. 

But behind the cipher-locked door leading to NSA's headquarters in Vietnam, a different picture was beginning to emerge from analysis of enemy intercepts. 

Twenty-three years earlier, a large and excited crowd had gathered in Hanoi's Ba Dinh Square, a grassy, festively decorated field a short distance away from the graceful homes in the French district. They had walked there on callused feet as tough as rawhide from the flooded rice fields of the Tonkin Delta, the muddy banks of the Red River, the docksides of Haiphong, and the sampans of Halong Bay. Bac Ho, the man they came to see and hear, stood before them, awkward and slightly stooped. A frayed khaki tunic covered his skeletal frame, his feet were clad in worn rubber sandals, and wispy black hairs hung from his bony chin like dandelion fluff. 

As the din of the crowd began to fade, Bac Ho stepped forward on a wooden platform, his glasses flashing in the sunlight. "We hold the truth [sic] that all men are created equal," he said solemnly, borrowing a phrase from the American Declaration of Independence, "that they are endowed by their Creator with certain unalienable rights, among them life, liberty, and the pursuit of happiness." The men and women in their drab pajamas and conical straw hats exploded as Bac Ho, a onetime resident of Brooklyn, gave birth to the Democratic Republic of Vietnam. By then, most knew him simply as Uncle Ho. Those in the United States would later know him more formally as Ho Chi Minh— Bringer of Light. 

In a land that had known little but torment, for a brief afternoon in September 1945, the sun had never shined brighter. Like a tired horse that has bucked off its last abusive owner, Vietnam had finally rid itself of its French and Japanese masters. Gangly and serious, Ho Chi Minh looked more like a shy chemistry professor than the leader of a guerrilla army. Born in central Vietnam in 1890, he traveled widely as a merchant seaman, spent time in the United States, learned seven languages, and saw communism as the most effective way to unite his country to expel the colonialists. After an absence of thirty years, Ho slipped back into Vietnam in 1941 disguised as a Chinese journalist. There he formed the Vietnam Independence League—the Viet Minh—to beat back the French colonizers, who had enslaved his country for decades, and the Japanese warlords, who were attempting to take over much of Asia. 

As the Allied and Axis powers battled in Europe and Japan, Ho fought his own war in the jungles of Vietnam—then French Indochina—using ambushes in place of howitzers, and sabotage instead of bombers. After four years of trial and error, he could have taught a doctorate-level course on the strategy of guerrilla warfare. Finally, with the end of World War II and the defeat of Japan, which was then occupying the country, Ho saw Vietnam's opportunity for independence, which he proclaimed on September 2, 1945. Unbeknownst to Ho, by the time of his proclamation America was already secretly eavesdropping on his new country. 

Although defeated by Allied forces in August 1945, the Japanese occupiers remained in Vietnam for another six months. During that time, American intercept operators and codebreakers monitored communications to Tokyo from Japanese outposts in Hanoi and Saigon. "Japanese reports back to Tokyo in the days before and immediately after the surrender," said a later NSA report, "provide some indication of how deep was the desire to throw off the yoke of colonialism, how strong the will to resist the return of the French." The intercepts carried reports of Ho's forces secretly taking into custody important Frenchmen, and "at nighttime there was gunfire." Another said, "when one considers the situation after the Japanese Army is gone, he cannot fail to be struck with terror." 

Not yet willing to give up their profitable rubber plantations and their global prestige, the French colonizers moved back in the spring of 1946 as the Japanese were pulling out. In so doing they arrogantly rejected the postwar trend to begin loosing the chains of foreign domination, and once again began to brutally exploit their distant colony. The moment of sunlight had passed; Ho's war would continue in the darkness. In November shooting erupted in Haiphong and the French bombarded the city, killing some 6,000 Vietnamese. On December 19, the Vietnamese attacked the French. As an NSA report says, "Thus began the Indochina War." 

In the United States, State Department Asian experts cautioned President Truman that Vietnam was a powder keg and that pressure should be put on France to grant the country "true autonomous self-government." The alternative, it warned pointedly, would be "bloodshed and unrest for many years, threatening the economic and social progress and peace and stability" of the region. CIA analysts counseled that providing military aid to France to crush its indigenous opposition "would mean extremely adverse reactions within all Asiatic anti-'colonial' countries and would leave the U.S. completely vulnerable to Communist propaganda." 

Nevertheless, while mouthing hollow platitudes about freedom and independence throughout the world, Truman agreed to help France remount its colonial saddle, sending millions of dollars in aid, weapons, and U.S. forces to help them fight Ho and his rebels. At one point in 1952, a witless CIA officer at the U.S. embassy in Hanoi hired a team of Chinese saboteurs, gave them some plastic explosives from his stockpile, and sent them off to blow up a bridge. That they failed in their mission should have been taken as a sign, like a fortune in a Chinese cookie. But the blunders would only grow larger and more violent over the next two decades. 

Eisenhower also weighed in on behalf of colonialism, sending the CIA to help the French beat back Ho and his forces. In November 1953, French paratroopers occupied Dien Bien Phu in northwestern Vietnam, ten miles from the Laotian border. Their plan was to lure Ho's rebel army into a trap in which they would be slaughtered by superior French firepower. But the French miscalculated and suddenly found themselves isolated, unable to keep resupplied by air. As a result, Eisenhower agreed to an airlift using CIA men and planes to fly supplies back and forth from Hanoi's Cat Bi airfield to Dien Bien Phu. 

The operation began on March 13, 1954, but the beleaguered French stood little chance and Dien Bien Phu fell on May 7. Over the two months it operated, the CIA flew 682 airdrop missions. One plane was shot down and its two pilots were killed; many other C-119s suffered heavy flak damage, and one pilot was severely wounded. 

Meanwhile, NSA secretly eavesdropped on the conflict. "I recall very dramatically the fall of Dien Bien Phu," said Dave Gaddy, an NSA official at the time. "There were people with tears in their eyes. . . . We had become very closely attached to the people we were looking over the shoulders of—the French and the Viet Minh. And we could very well have sealed the folders, put everything away, locked the files, shifted on to other things, and didn't. As a result, we had a superb backing for what came along later." 

Taking up where the French left off, CIA operations continued in Indochina after the fall of Dien Bien Phu. Between mid-May and mid-August, C-l 19's dropped supplies to isolated French outposts and delivered loads throughout the country. The French, driven by greed, would be replaced by the Americans, driven by anti-Communist hysteria. This despite a secret State Department intelligence report at the time saying that the department "couldn't find any hard evidence that Ho Chi Minh actually took his orders from Moscow." 

By the time John F. Kennedy entered the White House in January 1961, Vietnam was a wave in the distant ocean, barely visible; a thin white line slowly growing and building. The French, at Dien Bien Phu, had been forced out after eight years of fighting and scores of thousands of deaths. Left as a reminder was a ragged demilitarized zone (DMZ) that cut across the narrow middle of the country like a haunting dead zone; a no-man's-land separating the pro-Communist forces in the North from 242 the pro-Western forces in the South. Six hundred and eighty-five American advisers were now in Vietnam and the financial commitment since 1954 topped $2 billion. 

Pressured by the Pentagon, which was concerned over growing reports of Communist infiltration into South Vietnam, Kennedy ordered a few helicopter and Special Forces units to the area. Then the Army began lobbying to also send signals intelligence assistance. For years South Vietnamese officials had asked for NSA's help in locating and eliminating Ho's infiltrators from the North, the Vietcong. But Eisenhower had long rejected the requests, considering the information and techniques far too secret. 

Kennedy reluctantly gave in to the Army's pressure. During a meeting of the National Security Council on April 29, 1961, he authorized NSA to begin providing Sigint support to the South Vietnamese Army. Sharing such sensitive information with a foreign government was highly unusual, as reflected in the Top Secret/Codeword "Communications Intelligence Regulation" that authorized the transfer. Because "the current situation in South Vietnam is considered to be an extreme emergency involving an imminent threat to the vital interests of the United States," said the order, dissemination of Sigint to the South Vietnamese military was authorized "to the extent needed to launch rapid attacks on Vietnamese Communists' communications." 

Vice Admiral Laurence H. Frost, the director of NSA, ordered his military arm, the Army Security Agency (ASA), to begin immediate preparations. Within weeks the 400th ASA Special Operations Unit (Provisional), using the cover name 3rd Radio Research Unit and the classified NSA designation "USM 626," was airborne. On May 13, 1961, the spit-shined boots of ninety-three Army cryptologists stepped from a silver C-130 transport onto the tarmac of Saigon's Tan Son Nhut Air Base. It was the Year of the Buffalo, symbolizing patience, fruitful toil, and peaceful contentment, concepts that would be difficult to find in a country on the precipice of all-out war. Green to combat, the Sigint experts would have a difficult time hearing the enemy. 

Ho's twenty years in the underground taught him not only the art of guerrilla warfare, but also how to keep a secret. Within days of his declaration of independence, officials of the rebel government began addressing the issue of codes and ciphers. "In the first days of the revolutionary regime," said a North Vietnamese document obtained and translated by NSA, "an urgent requirement was to research methods of using cryptography so as to ensure communications security." Ho himself warned a class of budding codemakers: "Cryptography must be secret, swift, and accurate. Cryptographers must be security conscious and of one mind." 

By the time of the war with America, Ho was calling his code-makers "cryptographic warriors" and ordering them to prevent loss of their crypto materials at all cost. He would give examples of heroic deeds to emulate. In 1962, they were told, Petty Officer Third Class Bui Dang Dzuong, a cryptographer on a small ship, ran into fierce weather. Nevertheless, as the boat was sinking he "destroyed the entire set of [cryptographic] materials. . . . Big waves, heavy wind, and sapped of strength—Comrade Dzuong gave his life." In another example, two cryptographers were injured during an attack; one stepped on a mine "that snapped his leg" while the other's "ears deafened and ran blood." Nevertheless, they "calmly preserved the cryptographic system," and only after they were relieved by a replacement did they go to the hospital. Following the lectures, the youthful codemakers were sent "down the Ho Chi Minh trail into the South to strike America." 

The Vietcong cryptographers learned their lessons well. While throwing an electronic fishing net into the ether, they regularly reeled it back in bulging with American communications; but they seldom used radios themselves. While they listened to broadcasts from Hanoi on inexpensive transistor radios, they sent messages back to their commands with couriers, except in dire emergencies. For local communications, they often used radios with very low power, frustrating American eavesdroppers. 

From dusk to dawn, the Vietcong ruled, in varying degrees, more than half of the South. They marched over, under, and around the DMZ like worker ants. In the South, supporters were recruited and resisters often shot. 

Locating the guerrillas so they could be killed or captured was the job of the radio direction-finding specialists. Another operation, code-named White Birch, involved eavesdropping on the nests of Vietcong infiltrators. A third, dubbed Sabertooth, trained the South Vietnamese soldiers to intercept, locate, and process plain text voice communications. 

The art of codebreaking, however, was considered too sensitive to pass on to South Vietnamese students. 

Home for the 3rd Radio Research Unit was an old hangar within the South Vietnamese Army's Joint General Staff Compound at Tan Son Nhut Air Base. Temperature inside the un-air-conditioned building regularly exceeded 100 degrees, and when a monsoon downpour came, the water would rush in through the front door and flood the space several inches deep.

Separating the various sections were walls made of stacked C-ration boxes. The analysts worked on long tables constructed of plywood and scrap lumber, but because there were so few chairs, the table was made about four feet tall so they could stand up while working. The NSA  official assigned to the unit did little better. "As a civilian from NSA," he said, "I was fortunate. They made me a desk—two stacks of C-ration boxes with a piece of plywood laid across them—and gave me a folding chair." Living conditions for the NSA chief were much more comfortable. First assigned to the Majestic Hotel in downtown Saigon, he was later moved to a two-bedroom villa he shared with an ASA officer. 

Within seven months the Sigint force more than doubled. By December 1961, the secret organization had grown to 236 men, along with eighteen intercept positions. Listening posts stretched as far north as Phu Bai, near the DMZ, a choice spot to pick up valuable cross-border communications. The school for training South Vietnamese soldiers was set up at the South Vietnamese Army Signal Compound. 

In the field, the work was nerve-racking and dangerous. It was, said President Kennedy, a "war by ambush rather than combat," one made up of "guerrillas, subversives, insurgents, assassins." Among the first Army cryptologists to arrive in Vietnam was twenty-five-year-old James T. Davis, a pharmacist's son from Tennessee whose words rolled off his tongue with a honey-coated twang. Based at Tan Son Nhut, the specialist-4 was assigned to search for Vietcong guerrillas in the tangled, overgrown jungle of giant ferns and dirt paths near Saigon. Traveling with heavily armed South Vietnamese soldiers, he needed to get close enough to the rebels so that his PRC-10 mobile radio direction-finding equipment could pick up their short-range signals. But if he got too close, he would become the hunted rather than the hunter. It was a deadly game of hide-and-seek, in which the loser was attacked and likely killed and the winner survived for another day. 

Three days before Christmas in 1961, Davis climbed into his jeep and, accompanied by his team of South Vietnamese soldiers, set off for a new location to the west of Saigon. But about eight miles from the air base, muzzle flashes from automatic weapons cut across his path and he zigzagged to avoid the fire. A split second later he heard a loud boom and was thrown to the ground as a powerful land mine blew his jeep apart. 

Davis grabbed for his M-l carbine and he and the others opened fire. But by now they were surrounded, and within minutes nine of his South Vietnamese troops had been killed by machine-gun fire. A bullet crashed into the back of Davis's head and he collapsed on the ground. The Vietnam War had claimed its first American victim—a Sigint specialist. Two weeks later, the 3rd Radio Research Unit's secret headquarters at Tan Son Nhut Air Base would be named Davis Station. Eventually, a barracks at NSA headquarters would also bear his name.

In Washington, that remote wave was beginning to swell and head toward shore. Kennedy further Americanized the civil war, ordering the CIA to beef up its covert operations far above the DMZ. Late at night, out of carbon-black skies, billowing parachutes glided gracefully to earth. But the missions, to infiltrate heavily armed South Vietnamese commandos into the North, were doomed before they began as a result of poor security. Automatic fire instead of friendly faces greeted most of the teams as they touched down at their landing spots in the northern regions of North Vietnam. 

Soon after President Johnson moved into the White House, following Kennedy's assassination in November 1963, the once far-off swell became a tidal wave about to crash. By mid-1964 there were 16,000 U.S. troops in the country and the war was costing American taxpayers about $1.5 million a day. Giving up on the disastrous CIA infiltration scheme, Johnson instead ordered the Joint Chiefs to develop a much more aggressive—but still "plausibly deniable"—operation that would convince Ho to give up his war for the South. The answer was Operational Plan 34A—OPLAN 34A, in Pentagonese—an ill-conceived CIA/Pentagon scheme for sabotage and hit-and-run attacks against the interior and coast of North Vietnam. 

For a quarter of a century Ho had fought for an independent, unified Vietnam, successfully driving the heavily armed French back to Paris. Even Secretary of Defense Robert S. McNamara thought OPLAN 34A made no sense. "Many of us who knew about the 34A operations had concluded they were essentially worthless," he recalled years later. "Most of the South Vietnamese agents sent into North Vietnam were either captured or killed, and the seaborne attacks amounted to little more than pinpricks." 

Just as U.S. and South Vietnamese forces fought back against the guerrillas from the North, the North Vietnamese fought back against the commandos from the South, on both land and sea. 

Into the middle of the fighting sailed NSA. According to an NSA report, "By midsummer of 1964 the curtain was going up on the main event, and no single element in the United States government played a more critical role in national decisions, both during and after the fact, than the National Security Agency." 

For several years NSA's seagoing eavesdroppers, the Naval Security Group, had been searching for ways to conduct signals intelligence along the coastal areas of their high-priority targets. Long-range high frequency North Vietnamese naval communications could be collected at large, distant listening posts, such as at Kamiseya in Japan and San Miguel in the Philippines. Other medium-range signals could be snatched by the large NSA listening posts at Davis Station in Saigon and at Phu Bai, near the DMZ. But to snare short-range signals, such as walkie-talkie and coastal communications, the antennas and receivers would have to get close to the action. Off limits were the large 246 eavesdropping factories owned exclusively by NSA, such as the USS Oxford. And far in the future were the smaller, Navy-owned Sigint ships, such as the Pueblo.

The only alternative was to build Sigint shacks inside large steel antenna-sprouting boxes. These shipping-container-like huts would then be lowered onto a destroyer and sealed to the deck. The ship would then cruise close to a shoreline, like a spy at a party with a bugged olive in his martini glass. 

They were far from ideal. Unlike the dedicated Sigint ships, which were virtually unarmed and unthreatening in appearance, the heavily armed destroyers were designed to be threatening and their presence was provocative. At the same time, the amount of signals intelligence that could be collected in the steel box on the deck was minuscule compared with what the dedicated ships could gather. 

The Naval Security Group began conducting these Sigint patrols, codenamed DeSoto, in April 1962 with missions off China and North Korea. In January 1964, as they were planning the OPLAN 34A hit-and run operations, the Joint Chiefs ordered additional DeSoto patrols off the North Vietnamese coast, in the Gulf of Tonkin. The signals generated by the surprise coastal attacks, they assumed, would be a good source of naval intelligence for the Sigint collectors. In addition to voice communications, the locations and technical details of coastal radar systems could be captured. 

The first mission was conducted by the USS Craig in late February 1964. Resting on the ship's deck were both a Comint van for communications intelligence and an Elint van for radar signals. But upon spotting an American warship idling suspiciously a half-dozen miles off their coast, the security-conscious North Vietnamese navy quickly switched off virtually all nonessential radar and communications systems. Thus the Sigint take was poor. 

At the request of U.S. officials in Saigon who were planning the raids into North Vietnam, another DeSoto mission was scheduled for the end of July 1964. It was felt that if a DeSoto mission coincided with coastal commando raids, there would be less chance of another washout. Chosen to host the electronic spies was the USS Maddox, a standard Navy "tin can," as destroyers were known. But whereas other ships had been ordered to stay at least thirteen miles off the coasts of such countries as China, North Korea, and the Soviet Union, the Maddox was authorized to approach as close as eight miles from the North Vietnamese coast, and four miles from offshore islands. 

Like itinerant seamen, the Sigint vans would bounce from ship to ship, sailing off the coast of China on one tin can and then off the coast of North Korea on another. The crews also would change. One month a van might be filled with Russian linguists and the next with Chinese. "Home" for the vans was the port of Keelung in Taiwan. Because there were only a few available to cover a large area, they were very much in demand. The one lowered onto the deck of the Maddox had earlier been lifted from the deck of the USS MacKenzie, where, loaded with Russian linguists, it had eavesdropped off the Soviet coast. 

As the Maddox was about to enter the Gulf of Tonkin, tensions were very high. At My Khe, a gritty stretch of coarse, hard-packed sand at the base of Monkey Mountain, U.S. Navy SEALs were teaching South Vietnamese marines the science of inflicting the maximum amount of death and destruction in the minimum amount of time. The main base from which the raids to the north took place, the My Khe compound was made up of a series of "compartmented" camps divided along ethnic lines, and long wooden docks. Secretly run by U.S. forces, it was a land of white phosphorus rockets and black rubber boats. 

Late on the night of July 30, 1964, as moonlight rippled across the choppy Gulf of Tonkin, a raiding party of South Vietnamese commandos climbed aboard four large, fast patrol boats. Several of the type known as PTFs—or, appropriately, Nasty-class boats—were powered by diesel engines. The others were standard American-made, gasoline-driven PT boats. The vessels were armed with 57mm light infantry cannon. Bluish-gray exhaust gas shot from the rear of the guns, rather than the muzzle, to reduce the amount of recoil so that they would be steadier when used out of their mounts. 

In the early morning hours of July 31, about halfway up the North Vietnamese coast, the boats blasted away at two offshore islands, Hon Me and Hon Ngu, in the most violent of the South Vietnamese—U.S. raids thus far. 

As the boats were returning to My Khe later that same morning, their wake passed within four miles of the Maddox, then just north of the DMZ. Viewed by North Vietnamese coastal defense radars, the ships would have appeared to be rendezvousing. The Maddox may also have been perceived as standing guard, ready to fire at any boats seeking to cross the DMZ in hot pursuit of the heavily armed patrol boats. It was well known that the United States was behind virtually every South Vietnamese raid on the North. 

Throughout the day, the Maddox bobbed lazily about eight miles off the North Vietnamese coast, just above the DMZ, an area of good signal hunting. Sitting in front of racks of receivers in the cramped Sigint van, which had received a new coat of gray paint a few days earlier to make it look like a normal part of the ship, the intercept operators worked twelve hours on and twelve hours off. One of the intercept positions was dedicated to short-range VHP communications, picking up hand-held 248 radios and the chatter between vessels off the coast. The proficiency of the voice linguists was limited at best, but they had a tape recorder attached to the monitoring equipment and could save the conversations for later analysis. 

Two other positions were for intercepting high-frequency Morse code signals. Because of the vagaries of radio wave propagation, some of the North Vietnamese high-frequency signals could be better heard in the Philippines than right off the coast. But because the ship was mobile, it could also pick up high-frequency signals that might escape the fixed, land-based listening posts. Unlike some DeSoto missions, the Maddox did not have a separate Elint van; the two Elint operators worked instead on the ship's standard radar receivers, alongside the crew. Also in the van was an on-line encrypted teleprinter, which could print out highly classified messages from NSA exclusively for the Sigint-cleared cryptologic team. This link bypassed the ship's normal communications channels. 

Unlike the job of the Oxford and the other seagoing eavesdropping factories then being launched by NSA, the DeSoto patrols were "direct support" missions. Part of the job of the Sigint detachment was to collect intelligence on naval activities along the coast for later reports. But another was to provide area commanders with current, immediate intelligence support, including warning intelligence. On the Maddox, those cleared to receive such reports included the ship's captain, Commander Herbert Ogier, and also Captain John Herrick, the commander of the Seventh Fleet's Destroyer Division 192. 

The twin missions of the Maddox were, in a sense, symbiotic. The vessel's primary purpose was to act as a seagoing provocateur—to poke its sharp gray bow and American flag as close to the belly of North Vietnam as possible, in effect shoving its 5-inch cannons up the nose of the Communist navy. In turn, this provocation would give the shore batteries an excuse to turn on as many coastal defense radars, fire control systems, and communications channels as possible, which could then be captured by the men in the steel box and at the radar screens. The more provocation, the more signals. The ship even occasionally turned off all its electronic equipment in an effort to force the shore stations to turn on additional radar—and begin chattering more—in order to find it. 

The mission was made more provocative by being timed to coincide with the commando raids, thus creating the impression that the Maddox was directing those missions and possibly even lobbing firepower in their support. The exercise was dangerous at best, foolish at worst. In the absence of information to the contrary, the Navy had assumed that North Vietnam, unlike most U.S. targets, did not claim a twelve-mile limit. Thus the decision was made to sail far closer to shore than on normal  patrols in Communist Asia despite the fact that the United States happened to be engaged in combat with North Vietnam. In fact, North Vietnam also claimed at least a twelve-mile limit and viewed the Maddox as trespassing deep within its territorial waters. 

On August 1, when the Maddox was about halfway up the North Vietnamese coast, intercept operators in the van were busy eavesdropping on the shore stations tracking the ship's progress. Upon hearing them report the Maddox's distance and bearing they could "backplot" the signal to the station's location. 

About 8:30 P.M. (local time) the ship approached the island of Hon Me; the island was now within easy range of the Maddox's powerful cannons. Although no one on board likely knew it, survivors on shore were still cleaning up from the grave damage produced by the American planned South Vietnamese commando boat raid just two nights earlier. It may be that when those on Hon Me saw the U.S. warship loom large on the horizon in the gray twilight, the alarm went out that the shelling was going to begin again, this time with more powerful guns. 

Hours later in the Sigint van, the tenor of the messages suddenly changed. A high-level North Vietnamese message was intercepted indicating that a decision had been made to launch an attack later that night. Although no targets were named, Captain Herrick was awakened immediately and informed of the situation. The next message, however, mentioned an "enemy" vessel and gave the Maddox's location. The conclusion was that an order had gone out to attack the Maddox. By then it was about 2:45 A.M. Captain Herrick ordered all personnel to go to general quarters, increased the ship's speed, and turned away from shore. 

At about 11:30 A.M. the next day, August 2, crewmembers on the Maddox sighted five North Vietnamese navy attack boats about ten miles north of Hon Me. They had been sent from the port of Van Hoa, 145 miles to the north, to help defend the island from further attacks and hunt for the enemy raiders. Nevertheless, despite the danger, the Maddox continued its patrol, reaching the northernmost point of its planned track at 12:15 P.M. At that point it turned south, remaining about fifteen miles from shore. In the Sigint van, the messages intercepted had again become routine—supply orders, pier changes, personnel movements. 

Suddenly the mood in the box changed. An odd message had been intercepted, and as it was being translated its seriousness became clear. It was an order to attack the ship with torpedoes. 

By then three North Vietnamese torpedo boats had already pulled away from the island, waves lathering their bows like shaving foam as they reached thirty knots. Their goal was to trap the Maddox in a pincers move. They would pass the Maddox and then turn back, trapping the  ship between them and the coast, preventing its escape to the safety of the high seas. Told of the message, Captain Herrick immediately turned southeast toward the open ocean. The intercept had turned the tide. By the time the PT boats arrived the Maddox was racing out to sea, leaving them in its wake as they fired at the destroyer's stern. 

On board each swift sixty-six-foot aluminum-hulled PT boat were torpedoes packing a deadly wallop, each fitted with warheads containing 550 pounds of TNT. The three boats each launched one torpedo, but the fast-moving Maddox was beyond reach. 

After this near miss, Captain Herrick suggested that the remainder of his Sigint mission be called off. But the general perception in the Pentagon was that such action would set a bad precedent, since in effect the United States would have been chased away. Herrick was ordered to continue the patrol and another destroyer, the USS Turner Joy, was provided as protection. 

Shortly after the attack on the Maddox, it was clear to officials in Washington that the principal reason for the incident was the North Vietnamese belief that the ship was directing the commando raids. "It seems likely that the North Vietnamese and perhaps the Chi-Coms [Chinese Communists] have assumed that the destroyer was part of this operation," Michael Forrestal, the State Department's Vietnam expert, told Secretary of State Dean Rusk on August 3. "It is also possible that Hanoi deliberately ordered the attack in retaliation for the harassment of the islands." 

Yet with the Maddox still on its DeSoto Sigint patrol, it was decided to launch more commando raids on the day following the attack, August 3, this despite Secretary of Defense McNamara's firm belief that the operations were useless. Departing from My Khe, the same location as the previous mission, the four-boat raiding party sped seventy-five miles up the North Vietnamese coast to Cape Vinh Son and Cua Ron. There they shelled a radar station and a security post, the first South Vietnamese—U.S. attacks against a mainland target. In response, a North Vietnamese patrol boat took off in hot pursuit for about forty minutes before giving up. And once again, the government of North Vietnam connected the raid with the still-present Maddox. 

Captain Herrick was worried about how stirred up the North Vietnamese were over the latest OPLAN 34A shelling. Early the next morning, August 4, he cabled his superiors: 

Evaluation of info from various sources indicates that the DRV [North Vietnam] considers patrol directly involved with 34-A operations and have already indicated readiness to treat us in that category. DRV are very sensitive about Hon 251 Me. Believe this PT operating base and the cove there presently contains numerous patrol and PT craft which have been repositioned from northerly bases. 

Later, an analyst at NSA received intercepts indicating that another attack on U.S. destroyers in the Gulf of Tonkin was imminent. One of the messages, sent from North Vietnamese naval headquarters in Haiphong to a patrol boat, specified the location of the destroyers. Another message included an order to prepare for military operations, using the patrol boats and perhaps a torpedo boat if it could be made ready in time. NSA immediately notified the Pentagon and a few minutes later, at 7:15 P.M. (Vietnam time), informed Captain Herrick on the Maddox. 

An hour after NSA's warning, the Maddox sent out emergency messages indicating that it had picked up radar signals from three unidentified vessels closing fast. Fighters were launched from the Ticonderoga but thick, low-hanging clouds on the moonless night obscured the sea and they reported that they could see no activity. Nevertheless, over the next several hours, the two ships issued more than twenty reports of automatic weapons fire, torpedo attacks, and other hostile action. But in the end, no damage was sustained, and serious questions arose as to whether any attack actually took place. "Freak radar echoes," McNamara was told, were misinterpreted by "young fellows" manning the sonar, who "are apt to say any noise is a torpedo." 

Nevertheless, regardless of the doubts raised by talk of "radar ghosts" and "nervousness," in testimony before Congress McNamara spoke of "unequivocal proof" of the new attack. That "unequivocal proof" consisted of the highly secret NSA intercept reports sent to the Maddox on August 4 as a warning. Based largely on McNamara's claims of certainty, both houses of Congress passed the Tonkin Gulf Resolution, thus plunging the United States officially into the open-ended quagmire known as the Vietnam War. 

But it later turned out that that "unequivocal proof" was the result of a major blunder by NSA, and the "hard evidence" on which many people based their votes for the war never really existed. Years later Louis Tordella quietly admitted that the intercepts NSA used as the basis for its August 4 warning messages to the Maddox actually referred to the first attack, on August 2. There never were any intercepts indicating an impending second attack on August 4. The phony NSA warning led to McNamara's convincing testimony, which then led to the congressional vote authorizing the Vietnam War. 

"What in effect happened," said Ray S. Cline, who was CIA's deputy director for intelligence at the time, "is that somebody from the Pentagon,  I suppose it was McNamara, had taken over raw Sigint and had shown the President what they thought was evidence of a second attack on a U.S. naval vessel. And it was just what Johnson was looking for." Cline added, "Everybody was demanding the Sigint; they wanted it quick, they didn't want anybody to take any time to analyze it." Finally, he said, "I became very sure that that attack on August 4 did not take place." 

A quarter of a century earlier, confusion in Washington over Sigint warning messages resulted in calm at Pearl Harbor when there should have been action. Now, confusion over Sigint warning messages in Washington led to action in the Gulf of Tonkin when there should have been calm. In both cases a long, difficult pass was successfully intercepted, only for the players in Washington to fumble a few feet from the goal line. 

For nearly four decades the question has been debated as to whether the Pentagon deliberately provoked the Gulf of Tonkin incident in order to generate popular and congressional support to launch its bloody war in Vietnam. In 1968, under oath before the Senate Foreign Relations Committee, Robert McNamara vigorously denied any such plot: 

I must address the suggestion that, in some way, the Government of the United States induced the incident on August 4 with the intent of providing an excuse to take the retaliatory action which we in fact took. . . . 

I find it inconceivable that anyone even remotely familiar with our society and system of Government could suspect the existence of a conspiracy which would have included almost, if not all, the entire chain of military command in the Pacific, the Chairman of the Joint Chiefs of Staff, the Joint Chiefs, the Secretary of Defense and his chief assistants, the Secretary of State, and the President of the United States. 

McNamara knew full well how disingenuous this was. The Joint Chiefs of Staff had become a sewer of deceit. Only two years before the Gulf of Tonkin incident, his Joint Chiefs had presented him with a plan to launch a conspiracy far more grave than "inducing" the attack on the destroyers. Operation Northwoods had called for nothing less than the launch of a secret campaign of terrorism within the United States in order to blame Castro and provoke a war with Cuba. 

More than three years after the incident in the Gulf, about the same time McNamara was feigning indignation before the Senate committee, the Joint Chiefs were still thinking in terms of launching "pretext" wars. Then the idea was to send the Sigint ship Banner, virtually unmanned,  off dangerous North Korean shores, not to collect intelligence but to act as a sitting duck and provoke a violent response. Once the attack occurred, it would serve as an excuse to launch a war. 

These proposed wars would be hidden for decades from Congress and the public under classification stamps and phony claims of national security. 

George Ball, under secretary of state when the Tonkin Gulf incident took place, later came down on the side of the skeptics. "At the time there's no question that many of the people who were associated with the war," he said, "were looking for any excuse to initiate bombing. . . . The 'DeSoto' patrols, the sending of a destroyer up the Tonkin Gulf was primarily for provocation. ... I think there was a feeling that if the destroyer got into some trouble, that it would provide the provocation we needed." Ball had no knowledge of Operation Northwoods. 

Restless from a decade of peace, out of touch with reality, the Joint Chiefs of Staff were desperate for a war, any war. Thanks in large part to the provocative Sigint patrols and NSA's intercept mix-up, now they had one. 

With the passing of the Tonkin Gulf Resolution, the tidal wave that had begun as distant whitecaps came crashing down, eventually sweeping tens of thousands of Americans to their death. 

At the same time the war was being fought in the steamy jungles, it was also being waged high in the ether. This was the Sigint war, an invisible battle to capture hidden electrons and solve complex puzzles. As in World War II, it can often be the decisive battle. But the glory days of solving the German Enigma code and the Japanese Purple code had long since passed. With the North Vietnamese military and the Vietcong, NSA was discovering, the old rules had been changed. The eavesdroppers would have to start from scratch. 

Hidden from view, NSA rapidly increased its buildup in Vietnam. By 1964 the number of cryptologic personnel in the country had reached 1,747. Three hundred men now packed Davis Station at Tan Son Nhut in Saigon. The Navy sent a Marine Sigint detachment to Pleiku, where they targeted Laotian and North Vietnamese communications. And U.S. Air Force intercept operators began setting up shop in Da Nang. To coordinate the growing numbers of units, a secure communications network was built linking sites at Nha Trang, Can Tho, Bien Hoa, Pleiku, Da Nang, and Ban Me Thuot. Then, in order to communicate quickly and securely with NSA headquarters, an undersea cable was laid from Vietnam to the Philippines. Codenamed Wetwash, the cable carried a variety of traffic ranging from high-speed CRITIC circuits to intercepted North Vietnamese messages too difficult to decrypt in Vietnam. In the  Philippines, the Wetwash cable connected to another secure undersea cable that eventually terminated at NSA, in Fort Meade. 

In the far north, near the demilitarized zone separating North from South, 1,000 Sigint personnel were sent to Phu Bai, which became the cornerstone of NSA's expansion. Like electronic border police, intercept operators manned 100 positions in a windowless operations building, listening for indications of infiltration and guerrilla activity. Others eavesdropped on tactical communications by both North Vietnamese and Laotian Communist forces. The expansive base was supported by another 500 people and surrounded by high fences, barbed wire and concertina wire, and eleven guard posts manned twenty-four hours a day. 

But just as the numbers of people continued to grow, so did the problems. Although the school to train South Vietnamese soldiers was built and fully equipped, for years it had virtually no students because of the inability of the indigenous soldiers to pass NSA's rigorous security clearance requirements. More equipment and personnel in the field meant more intercepts, but most of them were not being analyzed because of the lack of trained linguists. "U.S. personnel with the ability to read Vietnamese texts were in short supply," said one NSA document, "and people competent to deal with spoken Vietnamese, with very few exceptions, were not to be found." Despite a crash training program at NSA, said the report, "the linguist problem became worse, not better." Communications problems were also frequent. 

Most incredibly, NSA deliberately refrained from mounting a massive World War II—style Enigma or Purple effort against North Vietnamese cipher systems. According to one of the key NSA officials overseeing the cryptologic effort in Vietnam, "We found that we had adequate information without having to do that. In other words, through a combination of traffic analysis, low-level cryptanalysis, and plaintext/clear voice. The situation didn't justify the major effort." According to another former official, mounting an enormous effort against North Vietnam would have diverted limited resources away from "the Soviet problem" and other areas, which nobody wanted to do. "And of course there was always the question of whether there was any utility in working on one-time pads," said the former official. "But my argument always was, How do you know it's a one-time pad if you don't work it?" This was an allusion to the surprising "Venona" breakthrough in Soviet onetime pads. 

For most of the intercept operators, used to the monotonous routine of peacetime listening posts, there was an air of unreality about Vietnam. The constant wharp-wharp-wharp of steel helicopter blades echoing off rusty corrugated roofs. Gunships on a hunt, flying in formation as they skimmed the ground. Open crates of green rocket-propelled grenades and saucer-shaped claymore mines resting haphazardly beside delicate flame trees and baskets of lotus blossoms. 

The Sigint war was fought by both sides. Although no one knew it at the time, the North Vietnamese Central Research Directorate, which managed the North's Sigint operations, was successfully collecting almost all South Vietnamese and U.S. communications passing over a number of key traffic lanes. North Vietnam did not need to break highlevel American codes, because the Americans continuously chose expediency over security. Rather than take the time to send the information over secure, encrypted lines, they would frequently bypass encryption and simply use voice communications. The problem became, according to NSA, America's Achilles' heel during the war. "There was no blotter large enough to dry up sensitive, exploitable plain-language communications in Vietnam," said one NSA report. 

Over the years, U.S. forces would occasionally capture enemy Sigint operators who would shed light on the problem. "Through interrogation of these men and study of the documents and signals intelligence materials seized," said a secret NSA analysis, "a clear, even frightening picture of Vietnamese Communist successes against Allied communications gradually emerged." Even as late as 1969, major clandestine listening posts were being discovered, such as one in Binh Duong Province. "Evaluation of the equipment showed that the enemy unit could hear virtually all voice and manual Morse communications used by U.S. and Allied tactical units. The documents proved the enemy's success—2,000 hand-copied voice transmissions in English and signals intelligence instruction books of a highly professional caliber." 

U.S. intelligence sources estimated that North Vietnam had probably as many as 5,000 intercept operators targeting American communications. "The inescapable conclusion from the captured documents in U.S. hands," said the NSA report, "is that the enemy is conducting a highly sophisticated signal intelligence operation directed against U.S. and Allied forces in South Vietnam. He has developed the art of intercept to the point where his operators receive training materials tailored to the particular U.S. or Allied units against whom they are working. The training materials captured list selected [U.S.] units, the frequencies on which they communicated, their communications procedures, the formats and numerous examples of their messages, and other characteristics to guide the communist operator." 

The consequences of the poor U.S. communications security coupled with the advanced state of North Vietnamese Sigint were serious. NSA labeled the careless procedures "deadly transmissions." Lieutenant General Charles R. Myer, a career signals officer who served twice in  Vietnam, outlined the problem. "The enemy might disappear from a location just before a planned U.S. attack," he said. "B-52 bomber strikes did not produce expected results because the enemy apparently anticipated them." 

Strikes from sea were equally vulnerable. On February 11, 1965, the aircraft carrier USS Hancock was preparing to launch a bombing raid against certain shore targets in the North. But details of the mission were discussed over plain-language channels days before the attack. As a result, North Vietnamese naval units were ordered to use camouflage and systematically disperse before the morning of February 11. On other occasions, when the American planes arrived over their targets, antiaircraft weapons were waiting, pointing in their direction, with deadly results. 

Again in an attempt to avoid the time-consuming task of encrypting information using approved NSA ciphers and equipment, Americans would often make up their own "homemade" codes. "Their continued appearance on the scene has constituted one of the major Comsec [communications security] headaches of the war," a Top Secret/Umbra NSA report noted. "Even as late as the spring of 1969, the U.S. Air Force attaché in Laos, who was coordinating semi-covert U.S. air and other operations in that country, was sending most of his messages in a code he had made up himself." NSA's Air Force communications security specialists secretly eavesdropped on the attaché's communications. "They could completely reconstruct his code within eight to ten hours after each change," said the NSA report. "Since the attaché changed codes only every five weeks, most of his messages were susceptible to immediate enemy Sigint exploitation. The appearance and reappearance of codes of this type demand constant Comsec alertness." 

Even if U.S. forces did use secure encryption to pass sensitive information, such as dates and times for attacks, problems arose when that information was passed to the South Vietnamese military and they discussed it over less secure channels. The South's communications were particularly vulnerable to the Vietcong. For example, using captured American equipment the guerrilla force was able to pick up U.S. Special Forces communications transmitted through the South Vietnamese Air Force network. "It was . . . likely that they could gain all the intelligence they needed on the growing U.S. presence in Vietnam from [South Vietnamese Air Force] communications," said an NSA study of the problem. One former Vietcong soldier later told U.S. officials that as a result of Sigint his unit had never been taken by surprise over a ten year period and that they never had enough English-language linguists for all the communications they intercepted. 

Another major problem was the lack of secure telephones. The Vietnam-era secure phone, the KY-8, was far from the compact handset 257 of today; it looked more like a small safe. In 1965 there were 800 of the crypto machines in a warehouse in the U.S., but they had neither mounting brackets nor connecting cables. After what was described as "some tortuous evolutions," the first KY-8s eventually arrived in South Vietnam late in 1965 and over the next three years they were all distributed. An aircraft version, the KY-28, and a mobile unit, the KY-38, were also distributed. But there were not nearly enough secure phones. They were also very temperamental and prone to failure. Because they broke down in direct sunlight and high heat, they were also useless in places like bunkers. As a result, they did not solve the problem of classified talk on unsecure phones. "Signal security, particularly in voice radio transmissions," said General Myer, "was a major problem area throughout the period of combat operations in Vietnam." 

To help guard against sloppy procedures and compromises, NSA and its naval, air, and military arms conducted what was known as communications security monitoring. "In conventional Comsec operations," said one NSA study of the Vietnam War, "the monitor places himself in the role of the enemy. Selectively, he intercepts the communications of his own service and then reports on the intelligence he has—and the enemies could have—gleaned from them." The Comsec personnel would frequently work from the back of hot, antenna-covered, three-quarter-ton trucks. Surrounding them would be a variety of monitoring equipment, such as the TPHZ-3, which could listen to thirty telephone lines simultaneously. During 1967, Comsec operators eavesdropped on 6,606,539 radio-telephone conversations and more than 500,000 conventional telephone calls. 

At one point, such operations possibly saved the life of Lieutenant General Creighton W. Abrams, the deputy chief of the U.S. military command in Vietnam. As Abrams was about to board a helicopter on a flight north from Saigon to Phu Bai near Hue, the details of the mission, including the time, altitude, and route, and the names of the passengers, were transmitted in the clear. Comsec monitors overheard the transmission and reported it immediately. As a result, the flight plan was changed. North Vietnamese intercept operators also overheard the transmission. Although Abrams flew by a different route, one of the other helicopters scheduled to make the trip was not told of the change. As a result, "it was shot at the whole way from Saigon to Phu Bai—an unusual effort by the VC who did not usually shoot at helicopters on such flights," said an NSA report on the incident. "This I believe was a certain example of enemy Sigint use." 

North Vietnamese Sigint experts were also able to pass false and deceptive information over U.S. communications links and at other times were able to trick American personnel into passing sensitive information to them over the phone. NSA called such "imitative communications deception (ICD)" the "capstone of the enemy's Sigint operations." During one period, at least eight American helicopters were downed as a result of ICD. 

At the U.S. air base in Da Nang, a Vietcong guerrilla killed an American base guard and then picked up his phone. Speaking English, he announced that the far end of the base was being attacked. When the guards rushed off to the far end of the field, the Vietcong attacked with little resistance. The damage to the base and its planes was estimated to be around $15 million. The incident could have been prevented if the guards had simply used a proper authentication system. 

At another point, guerrillas were able to lure American helicopters into a trap by breaking into their frequencies, using correct call signs, and then directing the choppers to a landing spot where they were ambushed. There were also numerous times in which American air and artillery strikes were deliberately misdirected to bomb or fire on friendly positions. At other times, the guerrillas were able to halt attacks by giving false cease-fire orders. 

Even the best NSA encryption systems then available were potentially vulnerable. These included the KY-8 for secure voice communications and the KW-7 for highly sensitive written messages. "All of our primary operational communications were passed on KW-7 secured circuits," one U.S. commander in Vietnam told NSA. "Thus, for the more important traffic, we had good security." 

But both the KW-7 and the KY-8 were captured by North Korea and turned over to Russia in 1968, and for years, until long after the Vietnam War ended, the Soviets were also getting up-to-date keylists for the machines from the Walker spy ring. This has led to speculation that the Soviets passed some of this information to the North Vietnamese. 

Former KGB Major General Boris A. Solomatin, chief of station at the Soviet Embassy in Washington from 1965 to 1968, denies that Walker contributed to America's defeat: "Walker is not responsible for your failures in bombing in North Vietnam." Solomatin, who retired from the KGB and still lives in Moscow, added, "If you decide that the information from Walker was not handed over to the North Vietnamese or our other allies, you will be making the correct one." 

But Solomatin's deputy at the time, KGB Major General Oleg Kalugin, who defected to the United States and now lives in Washington, disagrees. Although the machines and their keylists were considered far too sensitive to turn over to the North Vietnamese, the Russians certainly helped the North Vietnamese whenever they could. "We certainly provided the Vietnamese with some of the product we had obtained through John Walker, and ultimately with the Pueblo's stuff we had from the North Koreans," said Kalugin. "The Soviet military were . . . quite involved in Vietnam. Not only in terms of providing military equipment, hardware and weapons, but also in helping the Vietnamese to conduct military operations, and to brief them on certain issues which the Soviets thought would have winning implications for the Vietnamese side." Kalugin added, "By providing the intelligence we had obtained . . . I'm sure we would help the Vietnamese. I'm sure we did." 

The Soviets also provided help in other ways. On June 18, 1965, on a runway on Guam, twenty-seven Strategic Air Command B-52 bombers lined up like a rehearsal for doomsday. They were a fearsome sight: planes as long as sixteen-story buildings, their swept-back, fuel-laden wings spanning more than half the length of a football field and drooping so close to the ground that they needed to be supported by bicycle-like outriggers. Weighing them down were eight Pratt & Whitney J-57 turbojets capable of generating more than 100,000 pounds of earthshaking thrust. Their cavernous bomb bays were roomy enough to house limousine-size nuclear bombs. 

In the cockpit of the lead aircraft, the gloved right hand of the pilot grasped the eight throttles, one for each engine. Slowly, in a single motion, he shoved them forward, hurling the mighty machine ever faster down the runway. Seconds later the plane lifted into the sky from Anderson Air Force Base, bearing fifty-one conventional bombs totaling sixteen tons. More than two dozen Stratofortresses followed, flying to a point over the measureless Pacific Ocean where they rendezvoused with a fleet of KG-135 tankers. There, through long steel straws, they took in fuel at 6,000 pounds a minute while performing a delicate ballet five miles above the sea at 300 miles an hour. 

Codenamed Operation Arc Light, their mission was to lay waste South Vietnam—the country the U.S. was trying to save. The targets were Vietcong guerrilla bases, which were to be bombed back into the days of flint and stone axes. Launched on their nonstop, 5,000-mile round-trip missions, the B-52s cratered the South Vietnamese countryside like the face of the moon. Twelve hours after taking off, they would land back on Guam. Month after month, 8,000 tons of iron rain fell on South Vietnam, spreading death, dismemberment, and destruction on whomever and whatever it touched. An average of 400 pounds of TNT exploded somewhere in the small country every second of every hour for months on end. 

As preparations got under way days in advance for each mission, a growing cloud of electrons would form over Guam. Messages would have to go out requisitioning new bomb fuses and brake pads, target recommendations would flow back and forth, authorizations and go orders would be transmitted. The volume of signals would increase every day, like a bell curve.

Shortly after the Tonkin Gulf Resolution was passed, a Soviet trawler, the Izmeritel, took up residence three miles off Apra, Guam's major harbor. Like a seagull hovering around a fish factory, the antenna covered Sigint boat was scavenging for signals. With the start of the Arc Light missions, the feeding became a frenzy. Guam served as a key communications center for many of the Navy's operations in Southeast Asia, and during the early part of the war was the only staging area for B-52 bombing missions over Vietnam. Soon after the beginning of Arc Light, mission planners began noticing that on many occasions the element of surprise had been lost. It would be more than a year before they began to understand why. 

Bobbing innocently in the waves off Apra, the Izmeritel was able to gain a clear picture of launch times for the B-52s. Through traffic analysis of pre-strike encrypted transmissions, they were able to identify alerts from the indicators that marked Flash messages. About an hour before launch, the short-range VHF radio network would swell with cleartext transmission by aircraft and munitions maintenance personnel. This increased volume tipped off the Soviets to an impending launch like a signalman waving a flag. Also, thanks to radio talk such as "652 must be ready by 0900," they were able to identify the launch aircraft by tail numbers and even to learn the names of the crew. Unencrypted weather forecasts by SAC over certain areas of the Pacific gave away the aerial refueling locations. 

Similar Sigint operations by the Vietcong in South Vietnam would reveal the target areas. And because the B-52s carried no encryption equipment, except for the Triton codes for nuclear authorization, all their communications were in clear voice. Captured enemy documents included a transcript of two and a half hours of detailed discussion of a particular planned B-52 raid, including the exact time of the attack and the coordinates of the target. 

Only after a highly secret NSA, Air Force, and Navy investigation at Guam and other locations was it determined how the North Vietnamese and Vietcong were able to eliminate Arc Light's element of surprise. The probe uncovered "a number of insecure communications practices that made vital intelligence available to the enemy." 

The NSA was also concerned about the Soviet trawler's ability to break its codes by discovering a "bust." Known technically as a cipher-signal anomaly, this is when an electrical irregularity occurs during encryption that "might permit an alert enemy to recover plain language or other data," according to an NSA document. Then, as now, it is a key way to break an otherwise unbreakable cipher. 

Even without a bust, the Soviet trawler might still be able to defeat the cipher systems by intercepting the radiation emitted from the cryptographic equipment. For years NSA had worried about the amount of intelligence that might be gained by monitoring the radiation emitted by sensitive communications and encryption equipment—even by power cords. Through careful analysis, these radiated signals might reveal the contents of a secret message as it was being typed on a cipher machine— that is, before it was encrypted. Likewise, an incoming message might be detected as it was being printed out, and thus at a time when its protective ciphers have been stripped away. To help eliminate or at least decrease this radiation, the agency has long had a program known as "Tempest testing." 

An NSA team was flown to Guam and put aboard the USS Charles Kerry, a destroyer, which was then positioned near the Izmeritel. Working inside a cramped Sigint van, the intercept operators began testing the electronic environment to determine just what the Soviet trawler was capable of hearing. Then the destroyer moved to other locations, eventually working its way around the island, staying three miles offshore. During the course of the test, the NSA team obtained over 77,000 feet of magnetic tape recordings. Happily, while in the vicinity of the Sigint trawler, the team could detect no "compromising cipher-signal anomalies," nor any Tempest problems. Nevertheless, at every point around the island they were able to clearly hear Air Force ground maintenance crews. "The communications were in plain language," said the NSA report, "and the NSA analysts could thus predict B-52 mission launchings at least two hours prior to take-off." 

After their seagoing survey, the NSA team tested the land-based circuits and found that signals from teletypewriters that were rapping out decrypted, highly secret messages were leaking onto unencrypted voice channels. Thus by intercepting and then closely analyzing the voice communications, the Soviets might be able to read the classified messages. 

As a result of the investigation, NSA conducted several other large scale analyses of communications leaks. One, codenamed Purple Dragon, determined that the North Vietnamese were learning the locations of planned strikes by several means, among them the monitoring of unencrypted radio traffic from the fleet of KG-135 tankers. 

To many at NSA, the results were shocking. "U.S. air strikes were of dubious success against an enemy who mysteriously faded from target areas," said a former NSA deputy director for communications security, Walter G. Deeley. "Ground sweeps seldom encountered more than the aged and the very young; and Marine amphibious forces stormed virtually deserted shores. It was apparent that the success of the enemy in evading our forces was probably predicated on advance knowledge of our intentions." 

More shocking, said Deeley, was the fact that even after being informed by NSA of the devastating security lapses, the military refused to take any corrective action. U.S. military commanders in Vietnam frequently looked down on Comsec and paid no attention to the warnings. And communications personnel referred to them as "buddy fuckers" because they eavesdropped on American forces. In such cases there was little NSA could do. "Comsec monitors and analysts had an advisory role only and no power themselves to effect changes," said an NSA report. "For a variety of reasons commanders frequently ignored, or read sympathetically without action, the findings of the Comsec units." The consequences were often deadly. 

One U.S. Army commander at 1st Infantry Division headquarters was talking over his desk phone when someone came into his office and mentioned that a specific operation was to take place in a location "35 kilometers north of here tomorrow." A Comsec monitor, eavesdropping on the call, heard the mention of the location of the operation and notified the officer. But the officer never bothered to change the plans. "On landing, the assault force met unexpectedly heavy resistance," said an NSA report. "U.S. losses were approximately 58 men killed and 82 wounded." The ASA commander on the scene "regarded the outcome as the results of an enemy reaction to a security breach." The number of deaths caused by poor U.S. communications security and successful North Vietnamese Sigint became alarming. NSA spoke of "a veritable flood of intelligence for enemy Sigint exploitation and tactical application, a flood that spelled defeat or losses during many U.S. combat operations." 

Incredibly, the United States was losing the code war the same way Germany and Japan lost it in World War II. With the aid of the Russians, the North Vietnamese may have been getting access to intelligence from NSA's most secure encryption systems, gaining information like that obtained by breaking the German Enigma and Japanese Purple codes during World War II. Even without that, they were obtaining enormous amounts of Sigint, which frequently allowed them to escape destruction and, instead, target American forces. 

From the very beginning, American commanders had an arrogant belief in U.S. military superiority. They believed that the North Vietnamese military and jungle-based Vietcong—the "gooks"—were far too unsophisticated to be able to make sense of U.S. communications networks. After all, many commanders reasoned, how could an army of soldiers who marched on sandals made of used tire treads be taken seriously? "Most U.S. commanders in Vietnam," said an NSA study, "doubted that the enemy could conduct successful Sigint operations. These commanders reasoned that U.S. superiority in training, firepower, and mobility made Comsec of little importance." The commanders, like  their defeated German and Japanese counterparts during World War II, would be wrong. 

Compounding the problem, the American military commanders would also ignore a second lesson of World War II: they paid little heed to warnings derived through their own signals intelligence. 

On March 8, 1965, two Marine battalions stormed ashore at Da Nang, the first official combat troops to be sent into the war. By the end of the year, the number of American forces in Vietnam would swell to nearly 200,000. After a period of relative calm, the Vietcong erupted throughout the country on May 11. More than 1,000 poured over the Cambodian border, a growing weak spot, and brought down Songbe, a provincial capital about fifty miles north of Saigon. 

To help plug the Cambodian hole, the decision was made to send NSA's flagship, the USS Oxford, into the war zone. The Oxford would be the first seagoing Sigint factory assigned to Vietnam. The orders were transmitted to the ship on May 26 to set sail immediately for Southeast Asia. At the time, the Oxford was just completing a nearly four-month cruise off West Africa, where it had stopped at Lagos and Durban, among other ports. Now not only were the crew going to war rather than home, they were also told that from now on the ship's homeport would be San Diego instead of Norfolk, a blow to those with families on the East Coast. 

"In Africa we were looking at some of the local links," recalled George A. Cassidy, an Elint intercept operator on the ship. "Anything that could be Communist related. If we ever got anything Communist or Russian it was like a feather in our cap. That was our main goal, to get something that had to do with Russia." 

Then came the message from NSA. "We left Durban and were going around the other side of South Africa for some reason," said Cassidy. "It was about three o'clock in the afternoon. The captain came on and made an announcement. Guys were really worried. I mean, you had guys who had marriages almost on the rocks, and here they are, they're across on the other side of the world. Guys had houses, families, cars, kids, wives, lovers, whatever, everything on the East Coast, and we all said, Now we're going to Vietnam. ... I can tell you it was probably almost the same lowering of morale, in a different way, which we felt when Kennedy was shot." 

On the long voyage to Southeast Asia, Cassidy found a way to boost morale: he created a photomontage of pictures taken by crewmembers in the various houses of prostitution they had visited while on their many NSA Sigint voyages. "Crewmembers would take photos in the whorehouses and bring them back where another crewmember would develop the film," he said. "I would swear them to secrecy that they wouldn't show it to anyone on the ship, especially the officers, and I would keep an extra print of the good stuff. I kept it locked away, a place nobody could find. It was in a big metal can up in an air vent in the photo lab. 

"So after this happened [the orders to Vietnam], I was talking to some of the guys, and they said why don't you make up a big poster board of all these pictures and try to raise the morale a little. I said, 'I can't do this, I'll get killed.' So I went to the captain and I told him what my idea was and he said, 'Well, if they're not really bad, explicit photographs it probably won't be a bad idea.' So I went to each guy and asked if they would mind and nobody really minded. And we put it up in the mess deck one afternoon. And I'll tell you, it kind of brought the morale up a little bit. It was from photographs of guys with women in Durban, the Canary Islands; I had some from the Caribbean, even. And there were some from the Zurich Hotel in Valparaiso, Chile." 

In Asia, as elsewhere, all information concerning the Oxford was considered very secret. Unfortunately, that made life difficult for those who were sent from the United States to join it. One of those was John De Chene, who was trying to get to the Oxford from California. "They tried to keep the Oxford movements very highly classified," he said. "First we went to Subic Bay, Philippines, because that's where they had the Oxford listed. We arrived at Clark Air Force Base and took a bus for four hours over back roads to Subic. Once there, they told us it was actually at Yokosuka, Japan. So we took the bus back to Clark and flew to Yokosuka, only to be told they'd never heard of the ship. Later, however, someone said the ship was now off Saigon. So we flew to Saigon and they said no, not here, she's now at Subic. We went back to Subic and it wasn't there. Finally they sent out a fleet search. Well, it had been sitting for two months in dry dock in Sasebo, Japan. So they flew us in to a Marine base in Japan and then we had to take a Japanese train all the way down to the lower islands and got to Sasebo the next morning and there she was. We were probably in transit about a week." 

Once out of dry dock, the Oxford sailed to its assigned station in the Gulf of Thailand, a remote area near An Thoi on the southern tip of Phu Quoc Island. "We generally spent two months on station at our position on the border of Cambodia/Vietnam, copying and recording all communications, both foreign and friendly," said De Chene. "A lot of the time we were only about two miles off the coast." It was a very good position to eavesdrop on and DF [direction-find] the hundreds of units in the area." 

The ship would occasionally pull in to An Thoi so that Ray Bronco, the ship's postal clerk, could pick up and drop off mail. One day he accidentally discovered that An Thoi was also home to a prison camp for captured Vietcong. "I was on the back of a flat pickup truck with all these  bags of mail going to the U.S.," he said. "A C-130 troop transport flew in and landed on an airstrip. I was probably about fifty yards or less away. It turned and the tail end almost lined up to the back of the truck. The back door opened up and out ran about thirty to fifty screaming Vietcong. They came charging toward me. The Marines fired over their head. They didn't realize that there was an innocent bystander there. I still have flashbacks and post-traumatic stress over it." 

Later, the Oxford's sister ship, the USS Jamestown, was also ordered to the area. The Jimmy-T, as it was known, was assigned to the South China Sea around Saigon and the Delta region. "There was always a rivalry between our sister ship . . . and us," said Richard E. Kerr, Jr. "In the aft ops area, we had a huge wooden hand carved into the classic 'the bird' position. I do not know the story behind it, but I think it had some funny inscription like, 'From one sister to another.' " 

Down below, in the Oxford's forward NSA spaces, intercept operators listened with highly sensitive KG-14 multi channel receivers. To translate the information, the Sigint unit had linguists qualified in Lao/Thai, several Chinese dialects, Russian, and Vietnamese. Among the intercept operators on board was at least one qualified in Tagalog, the language of the Philippines. "We did as much processing as we could," recalled De Chene. "Fort Meade wanted both recordings and transcripts and our breakdowns of it. Pretty much full scope of as much as we could cover . . . For about two weeks we had one NSA guy on board. He kept to himself. I don't think anybody knew why he was there." In the aft area, Elint operators collected the signals of hundreds of radar systems on huge reels of Mylar tape attached to 32-track Ampex recorders. 

Among the most important assignments during the Oxford's years in Southeast Asia was the Seven Nations Manila Summit Conference, which took place in the Philippine capital on October 23—27, 1966. Anchored in Manila harbor, right across from the Stanley Point Naval Air Station, the ship was able to eavesdrop on the negotiations. Thus, American negotiators got a leg up by discovering the strategies and arguing points of the other players. At one point, intercept operators on the ship "uncovered a plot," said De Chene, "to assassinate [U.S. President Lyndon B.] Johnson, [Philippine President Ferdinand E.] Marcos, and I think Nguyen Cao Ky." The plotters were members of the Communist inspired Huk movement. As a result of the intercept operators' warning, every member of the ship received a letter of commendation. 

The Sigint personnel and the rest of the ship's crew, referred to as general service personnel, were in effect segregated. "The general service personnel had no idea what we did, or how we did it," said De Chene. "All they knew was at the commencement of the workday, we would file behind those security doors, both fore and aft of the ship, and we would reappear at noon for chow. For the most part, they stayed away from us and in greater or lesser degrees, we, them. It was as if there were two different Oxfords, and I guess there really were." Ray Bronco agreed: "They [the Sigint personnel] were in a world of their own." 

In July 1966, NSA decided to have the Jamestown temporarily relieve the Oxford and send Oxford to conduct signals intelligence operations along the coast of mainland China. At the time the secretive and violent Cultural Revolution was going on. "After about two weeks of cruising up and down China's coastline," said De Chene, "our results were fairly meager at best. From all appearances, the Chinese knew when and where we were going to be and for the most part, their communications transmissions were held to a bare minimum, or none at all." 

But while the eavesdropping proved quite boring, the South China Sea gave them more excitement than they desired. Typhoon Ora was moving rapidly toward the Oxford, "We were taking severe rolls," De Chene recalled, "and the storm was growing stronger. The following day all hell broke loose. We lost a boiler and we were now dead in the water, almost at the center of the typhoon. We were drifting, and the wind was pushing us right into the coastal waters of Red China." 

An emergency message went out for help and a fleet tug was dispatched for rescue. But more than a day went by without any sign of help. "All hands were now briefed on our full situation," said De Chene, "and advised that an abandon ship order might be given, and the CTs [communications technicians] were put on standby to destroy all equipment and documents. The captain also considered putting our utility boat and his gig in the water to possibly either start towing the ship or at least slow her drift. At this point we were approximately twenty miles from the beach, or eight miles from Chinese coastal waters. Finally, after drifting inland for two more miles, the tug made its appearance and shot us her lines. She then towed us back to Taiwan and out of harm's way of both capture and the storm." 

The war in Vietnam was layered, like a wedding cake, and it was fought from the ground up. After the ambush death of James Davis as he prowled through the jungle near Saigon attempting to pinpoint enemy signals, NSA began experimenting with direction finding from the air. "Since radio wave propagation in Southeast Asia required that DF equipment be very close to the transmitter," said an NSA report, "the obvious answer was to go airborne." 

While some airborne Sigint and DF missions required enormous planning, others were seat-of-the-pants, such as the chopper missions. Flying near treetop level just south of the DMZ were intercept operators in UH-1H "Huey" helicopters. With antennas duct-taped to the chopper's skids, the operators searched for North Vietnamese Army communications signals. Inside, a Vietnamese linguist listened for infiltrators through earphones attached to a captured North Vietnamese Army backpack radio. "They used to make them out of their beat-up green .50-caliber ammo cans," said one intercept operator. "It had a few dials on it with Chinese characters." 

The pilots on board had KY-58 secure voice systems to quickly and secretly pass the time-sensitive information back to base. "Most of the time we were flying we picked up their communications," said the intercept operator, "so you would get a lot of information. But it would be very time-critical. The units were always on the move, so if you didn't get the information back really quick it would be of little use. Tactical intelligence is very of-the-moment, versus strategic, which is long-range, overall planning." Once NVA units were located, airborne or ground troops would be sent in after them. 

Unlike the other services, the Army had paid little attention to airborne Sigint since the end of World War II. Throughout the 1950s, Army intercept operators flew missions in Navy aircraft. The codename of one of their operations in the early 1960s, also aboard a Navy Sky Warrior, seemed to sum up the problem: Farm Team. It was at that point that the Army decided to invest both manpower and funds in developing its own professional team of aerial eavesdroppers. By March 1962 the Army Security Agency had its first airborne DF platform, the RU-6A De Havilland Beaver, a single-engine aircraft that flew low and slow and had room for very few operators. Within days, intercept operators in the unit were calling it TWA: Teeny Weeny Airlines. 

Far from the sleek, high-flying U-2 or the lightning-fast SR-71, the early Sigint planes in Vietnam were almost comical. "The operators hung a long wire out the back of the aircraft for a crude direction-finding antenna," said one veteran. "Crews flew in hot, humid conditions in very loud aircraft. Missions were often four hours long, but could be longer depending on the operational tempo of the forces in contact." The planes may have looked funny, but they provided vital information. "It has been said," the veteran reported, "that air missions produced as much as one third of the intelligence known to ground forces." 

Later, a more advanced aircraft joined the fleet of Beavers. This was the RU-8D Seminole, a stubby black twin-engine with room for five passengers. Tall thin blade antennas protruded vertically from the tips of the wings, giving the diminutive spy plane a somewhat menacing look. 

Richard McCarthy was one of those who volunteered for the 3rd Radio Research Unit's 224th Aviation Battalion. Flying out of Tan Son Nhut Air Base, McCarthy would often be assigned to the Saigon River Delta area, an inhospitable, mosquito-ridden wedge of swamp that stretched from Saigon to the sea. Because it was also the main shipping channel to Saigon, it became a haven for pirates and small groups of Vietcong guerrilla fighters. "Whoever controlled the shipping channel controlled Saigon," said McCarthy. 

Because the Delta area was so compact, the single-engine Beaver was preferred. Wedged behind the copilot, the plane's skin to his back and two Collins 51S1 receivers in front of him, McCarthy would be listening for enemy communications through one of his helmet's earphones, and to the Beaver's pilot and copilot through the other. Navigation consisted of looking out the window for landmarks, and wads of masking tape were applied to the doors to prevent the plotting sheets from being sucked out. 

Two hours into one mission over the Delta, McCarthy's earphones began buzzing—the familiar sound of a guerrilla tuning his transmitter for a call. "He was good and he was loud," said McCarthy. "It was show time." In an attempt to locate the guerrilla's transmitter, the pilot would twist and turn the plane back and forth to obtain different bearings on the target. Once the enemy forces were plotted, the crew would call in an air strike. 

As NSA began sending more and more airborne eavesdroppers to Vietnam, the sky became an aviary of strange-looking metal birds hunting for signals to bring back to their nests. Two miles above the choppers and puddle jumpers was the EC-121M "Big Look," a Lockheed Super Constellation with monstrous radomes on its top and bottom. To some, the plane resembled a humpbacked and pregnant dinosaur. Because it was heavy and the cabin wasn't pressurized, it was limited to about 10,000 or 12,000 feet. Lined up along the windowless bulkheads, the intercept operators attempted to squeeze every electron of intelligence out of the ether during each twelve-hour mission, providing warnings to U.S. attack aircraft. 

Warnings were critical. In the late spring of 1972, General John Vogt dispatched an eyes-only message to the Air Force Chief of Staff, General John Ryan, frankly stating that the 7th Air Force was losing the air war. The problem, Vogt said, was the increased proficiency of North Vietnamese pilots and their ability to make single, high-speed passes while firing Atoll missiles. Facing them were inexperienced U.S. pilots rotating into the combat zone every year. 

NSA came up with Teaball, a system in which detailed warnings based on Sigint were quickly sent to the pilots. Many at the agency opposed the idea of broadcasting in the clear such secret information, but the concept was eventually approved. 

Teaball was set up in a van at NSA's large listening post at Nakhon Phanom in northern Thailand. There, intercept operators would broadcast to the fighters, via a relay aircraft, the latest Sigint on surface to-air missile sites and MiG fighters in their area. When Sigint revealed that a specific U.S. aircraft was being targeted for destruction, the pilot, nicknamed "Queen for the Day," would be instantly notified. "Naturally, that particular flight element began to sweat profusely," said Doyle Larson, a retired Air Force major general involved in Teaball, "but all other strike force elements relaxed a bit and let Teaball take care of them." A veteran pilot and Sigint officer with over seventy combat missions in Vietnam, Larson said that "Teaball was an instant success." The kill ratio for American fighters attacking North Vietnamese MiGs "increased by a factor of three." 

Above the choppers, the Beavers, the Seminoles, and Big Look were the RC-135 flying listening posts—Boeing 707s filled with intercept operators and super-sophisticated eavesdropping equipment. From Kadena, Okinawa, the planes would fly daily twelve-hour missions, codenamed Burning Candy and Combat Apple, to the Gulf of Tonkin.

Eventually, as the war heated up, more and more missions were flown, until an RC-135 was constantly on station in the northern Tonkin Gulf twenty-four hours a day. It was an incredibly demanding schedule. Each mission lasted just over nineteen hours, including twelve over the Gulf. Two missions were flown every day, with a third aircraft on standby, ready for immediate launch if the primary aircraft had a problem. All the while, the five RC-135s in the Far East were also needed to cover the numerous Sino-Soviet targets. The missions took their toll not only on the crews but on the aircraft, the corrosive salt spray and high humidity ulcerating the planes' aluminum skin.

The North Vietnamese air force knew full well the purpose of the aircraft and would occasionally try to shoot it down. "MiG-21s would streak out over the Gulf at supersonic speeds and make a pass at the RC-135," said veteran Sigint officer Bruce Bailey. "Both fuel and fear limited them to only one pass. They would fire everything they had and run for the safety of their AAA [anti-aircraft artillery] and SAM [surface to-air missile] umbrella back home." Although the RC-135 was a prize target, none was ever lost to a MiG.

Wherever they flew, the RC-135s were electronic suction pumps, especially the RC-135C, nicknamed the "Chipmunk" because of its large cheeklike antennas. The reconnaissance systems on board were programmed to automatically filter the ether like kitchen strainers, "covering the electronic spectrum from DC [direct current] to light," said Bailey. "It had such a broad coverage and processed so many signals at such an incredible rate it became known as the ‘vacuum cleaner.' It intercepted all electronic data wherever it flew, recording the information in both digital and analog format." 

At the same time, the Chipmunk's numerous onboard direction finders were able to automatically establish the location of each emitter for hundreds of miles. Sophisticated computers located signals that in any way varied from the norm, and highlighted them. Other key voice and data frequencies were pre-programmed into the computer and instantly recorded when detected. "The volume of data collected by that system was sufficient to require an entire unit and elaborate equipment to process it," said Bailey. "That large and impressive operation became known as 'Finder.' The amount of intelligence coming out of Finder was staggering. 

"With its vacuum cleaner capability and very little specific tasking in the war zone," said Bailey, "the Chipmunk spent only a couple of hours in the combat area on those missions. It went in, sucked up all the signals, let the two high-tech operators look around a little, then resumed its global tasks." 

Still another RC-135 variation, sent to Vietnam late in the war, was the RC-135U "Combat Sent," which had distinctive rabbit-ear aerials. It has been described as "the most elaborate and capable special mission aircraft ever . . . with technical capabilities that seemed like science fiction." 

Still higher in the thinning layers of atmosphere above Vietnam were the unmanned drones that could reach altitudes in excess of 12½ miles. "They were designed to intercept communications of all sorts: radars, data links, and so forth," said Bruce Bailey. "The intercepted data was then transmitted to other aircraft, ground sites, or satellites." Based at Bien Hoa Air Base near Saigon, the diminutive drones contained so many systems as to give rise to a joke: the Ravens claimed that they also contained "a tiny replica of a field-grade officer to take the blame for anything that went awry." 

The program proved very successful. On February 13, 1966, one of the Ryan drones "made the supreme sacrifice," said Bailey, but in the seconds before it became a fireball it intercepted and transmitted to an RB-47 critical information on the SA-2 missile, including the fusing and radar guidance data. The assistant secretary of the Air Force called it "the most significant contribution to electronic reconnaissance in the past twenty years." 

Above even the drones flew the U-2, the Dragon Lady of espionage. Following the shootdown of Francis Gary Powers over the Soviet Union in 1960 and Eisenhower's declaration that the U.S. would never again overfly Russia, the U-2 had been reduced to air sampling missions for nuclear-test detection and to peripheral missions; its glory days were seemingly behind it. Eventually, intelligence officials began to nickname the plane the "Useless Deuce." The Cuban missile crisis was only a brief shot in the arm, but after the Gulf of Tonkin incident in 1964, the U-2 was drafted into service for the Vietnam War. Although the aircraft started out performing the job it was most famous for—high-altitude photography—that soon changed. Because of the growing numbers of SA-2 missile sites—the U-2's weak spot—in North Vietnam, the planes were soon assigned exclusively to Sigint. 

Based initially in Bien Hoa Air Base near Saigon, and later moved to Thailand, the U-2s in Indochina were now the responsibility of the Strategic Air Command, not the CIA. Although happy with the new responsibility, the Air Force pilots found eavesdropping far more tedious than snapping pictures over hostile territory. "All I had to do was throw a switch and recorders on board would collect the bad guy's radar frequencies and signals, and monitor everything," said former U-2 pilot Buddy Brown. The Armed Forces Courier Service would then ship the tapes to NSA. 

The missions called for the planes to circle for a dozen or more hours in areas over the Gulf or Laos, listening primarily to Chinese communications targets. As more and more antenna blades were stuck to its skin, the once-graceful U-2 was beginning to resemble a porcupine. On board, the receivers were becoming increasingly automated. All the pilot had to do was to stay awake. The antennas would pick up the preprogrammed signals, and the onboard receivers would automatically transmit them down to Sigint analysts in South Vietnam, who could then retransmit them via satellite in near real time right to NSA. There, computers and cryptanalysts could immediately begin attacking them. 

"The pilot did not operate the receivers, as they were either automatic or remotely controlled," recalled Bruce Bailey. "He sat there boring holes in the sky for hours with very little to do or see. The only relief came from tuning in on the war, listening to radio calls from strike aircraft and rescue attempts. That helped keep him awake." 

As the systems became ever more automated, Sigint analysts on the ground were able to remotely switch from target to target via the U-2's electronics. "Those systems enabled the specialists to select signals of the most interest," said Bailey, "search for suspected emitters, operate the equipment as if they were aboard the U-2 and to relay their intelligence to users around the world via satellite and other communications." Eventually, the main thing keeping the pilots awake, according to Bailey, was simple discomfort. "Twelve hours is agonizingly long to wear a pressure suit, sit in one position, endure extremes in heat and cold, control your bowels, and feel your body dehydrating from the extremely dry air and the oxygen they had to breathe constantly." Nevertheless, he said, the aircraft's ability to linger in one area for extended periods, capturing thousands of conversations, made it "the king of Comint." 

"Throttles to Max A/B," said Air Force Major Jerry O'Malley just before his SR-71 nosed into the sky over Kadena Air Base. From Okinawa, just 272 after noon on Thursday, March 21, 1968, the Blackbird set out on its very first operational mission: to penetrate North Vietnamese airspace, record enemy radar signals, photograph missile sites, and be back in time for dinner. 

As the Blackbird sped at more than three times the speed of sound toward the hot war in Vietnam, it left behind a bureaucratic war in Washington. For nearly a decade the CIA and the Air Force had been secretly at war with each other over whose aircraft would become America's premier spy plane—the CIA's A-12 or the Air Force SR-71. They were virtually the same aircraft except that the A-12 was a single seater, covert (that is, its very existence was secret), and a bit smaller and older; and the SR-71 was overt and had room for a pilot and a reconnaissance systems officer. President Johnson decided to go with the Air Force version and, eventually, the CIA was forced out of the spy-plane business entirely. 

One step above the U-2 and one step below the Sigint satellites, the bullet-fast SR-71 Blackbird could penetrate hostile territory with impunity. It flew sixteen miles above the earth, several miles higher than the U-2, at more than 2,000 miles per hour; no missile had a chance against it. 

As Major O'Malley approached the Gulf of Tonkin at a speed of Mach 3.17 and an altitude of 78,000 feet, the top of his Blackbird was brushing against outer space. Outside, the air temperature was about minus 65 degrees Fahrenheit, yet the leading edges of the plane were beginning to glow cherry red at 600 degrees and the exhaust-gas temperatures exceeded 3,400 degrees. Above 80,000 feet, the curvature of the earth had a deep purple hue. In the strange daylight darkness above, stars were permanently visible. 

The Comint and Elint sensor-recorders were already running when O'Malley prepared to coast in for a "front-door" entry into North Vietnam at two miles a second. As the Blackbird followed a heading of 284 degrees, the onboard defensive systems indicated that the North Vietnamese clearly had them in their Fan Song radar, one of the types used by SA-2 missile batteries. Behind O'Malley, Captain Ed Payne, the reconnaissance systems officer, flipped a few switches and the Blackbird's electronic countermeasures prevented the radars from locking on as they passed over Haiphong harbor near Hanoi. 

"The SR-71 was excellent for 'stimulating' the enemy's electronic environment," said retired U.S. Air Force Colonel Richard H. Graham, a former SR-71 pilot. "Every time [they] flew in a sensitive area, all kinds of radars and other electronic wizardry were turned on to see if they could find out what was flying so quickly through their airspace. In fact, our missions were generally not Elint productive unless 'they' were looking for us with electronic signals." To capture the signals, the SR-71 used a piece of equipment known as the electromagnetic reconnaissance (EMR) system. At first, said Graham, "the EMR would literally sit there and record signals from hundreds of miles around the aircraft. It had no discretion on what signals it received, and made it very difficult to find specific frequencies out of the thousands recorded on one mission." 

But after an upgrade, known as the EMR Improvement Program (EIP), the SR-71 's Sigint capability improved considerably. "The EIP continuously recorded signals from horizon to horizon along our flight path," said Graham, "a distance of around 1,200 nautical miles. If the system recorded a specific frequency for a short period of time, computers could plot the precise position of the transmitter on the ground within approximately one half mile, at a distance of three hundred miles from the SR-71. . . . The EIP was very efficient at its job, at times often recording over five hundred emitters on a single operational sortie. ... It was a Star Wars version of eavesdropping." 

As the Blackbird entered North Vietnam's "front door," each of its two Pratt & Whitney J-58 engines was generating as much power as all four of the enormous engines on the Queen Mary. Just twelve minutes after entering, the Blackbird had crossed the country and was about to exit through the "back door." Passing over the Red River, O'Malley flicked the Inlet Guide Vane switches to the "Lockout" position and eased the throttles out of afterburner. After a second in-flight refueling from a "boomer"—a tanker—over Thailand, the Blackbird headed back to Vietnam. This time it passed over the DMZ in search of the heavy guns that had been assaulting Khe Sanh. In its few minutes over North Vietnam, analysts later discovered, it located virtually every missile site. 

For all the sophisticated ships, planes, and foreign listening posts, there were many who fought the Sigint war in the muddy swamps and steamy jungles, right alongside the combat troops. 

"As a member of the Army Security Agency you will never end up in a war zone," the reddish-haired Army recruiter in the neatly creased uniform confidently assured Dave Parks. "The ASA, because of the high level of security clearance, is not allowed to serve in a combat zone." That made sense, thought Parks as he walked out of the Atlanta recruiting station in 1965, having just signed up for four years. 

Two years later Parks, now an Army intercept operator, arrived in Saigon for a one-year tour in Vietnam. The recruiter had kept his promise, but Parks had volunteered. "I wanted to see a war," he said, "and Vietnam was the only one we had." Assigned to the 303rd Radio Research Unit at Long Binh, near Saigon, Parks quickly became aware of the dangers involved in the assignment. "In the event that you are  severely wounded would you like your next of kin notified?" a clerk casually asked him without ever looking up from the form. "Okay, in the event you are severely wounded do you want the Last Rites administered? We will need to make arrangements in case of your dying over here." Finally Parks asked what kind of a unit he was in. "Infantry," he was told. "A unit called the 199th Infantry." Parks gulped. 

"I had spent my six months of Advanced Individual Training at Fort Devens being threatened by the ASA instructors that if we students washed out of the course we would get a one-way ticket to the 196th Light Infantry," Parks recalled. "Now here I was eighteen months later being assigned to its sister unit. This might be more adventure than I'd bargained for. Volunteer for Vietnam, I should have known better." 

Parks's Sigint unit, the 856th Radio Research Detachment of the 199th Light Infantry Brigade, was made up of about fifty troops, headquartered at Long Binh. "Light infantry" meant light and mobile. The troops were equipped with only the most basic armament, such as rifles, machine guns, and grenade launchers. The largest caliber of weapon carried in the field was a 90mm hand-held recoilless rifle. The men were housed in a two-story wood-frame barracks surrounded by several layers of protective sandbags and topped with a corrugated-tin roof. The Sigint operations compound was encircled by a tall barbed-wire fence with coils of razor wire on top and to either side. Cover music blared from speakers to hide escaping signals; loud, rasping generators ran twenty-four hours a day; and there was a sandbagged guard shack at the only entrance. Intercept operations were conducted from two windowless vans that were parked backed up to the building. 

Parks, however, would spend little time in the operations compound. The mission of the 199th in November 1967 was to patrol, with South Vietnamese rangers, the vast rice bowl known as the Mekong River Delta. Spreading south of Saigon like a soggy sponge, the area was a maze of swamps, rice paddies, and waterways. Soldiers called walking in it "wading in oatmeal." In places it was covered by triple-canopy jungle, sometimes so dense that light had difficulty getting through. The map gave areas such descriptive names as Parrot's Beak, the Iron Triangle, and the Rung Sat Special Zone. The 199th's orders were to seek out and destroy Communist guerrilla infiltrators, mostly from Cambodia, and to act as a sort of quick reaction force in the event of a firefight. 

Operations were based at Cat Lai, a small village on the banks of the Song Nha Be River, a winding snake fed by a lacework of muddy canals and narrow streams. Like a liquid highway, the river carried countless cargo ships to the docks of Saigon, where they unloaded heavy tractors and foodstuffs and filled up with dusty bags of rice. As they lined up, bow to stern, waiting for their turn at the docks, the lightly protected ships were prime targets for the Vietcong, who would attempt to sink them. It was up to Parks and his fellow troopers to prevent that. 

Unlike most Sigint soldiers, who worked regular shifts at heavily protected listening posts, most far from the action, Parks fought side by side with the combat troops. A bandolier of ammo was strapped over one shoulder, and an M16 hung from the other. Canteens, poncho, bayonet, camouflage blanket, sleeping bag, and first-aid kit clung to his back or hung from his web belt. His job, as a DF operator, was to find the Vietcong before they found his fellow troopers. 

Cat Lai was little more than a few rows of grass huts and some red bougainvillea on the bank of a muddy river. The troops lived in tents erected over wooden platforms that served as floors. Two olive-drab vans were used as listening posts, with two intercept operators in each one. Wooden walkways led to a club, constructed out of plywood, that served Vietnamese "33" beer and mixed drinks. A short way down the road, alongside the river at the edge of the village, was an open-sided restaurant/bar/whorehouse patronized by the crews from ships lining the waterway. Like the small, rusty tubs anchored nearby, the crews came from every part of the world and the background conversations had a musical quality. Years later, when Parks saw the bar scene in the film Star Wars, he was reminded of the club. 

The prostitutes who served the crew also came from many parts of the world. One, a stunning woman with sparkling eyes and coal-black skin, came from Cameroon in West Africa. Her ex-lover had recently tossed her off one of the transports. With halting French and a little German, Parks agreed to a price. 

The work of the direction-finding teams had changed little in the seven years since DF specialist James Davis became the first American soldier killed in the war. It had only grown more dangerous. "Being on a DF team was about as far forward as you could get in the ASA in Vietnam," said Dave Parks. The Vietcong had shifted their priority targets from the South Vietnamese to the Americans. In a nearby province, the casualty rate for one American unit was running 40 percent. Out of about forty men, eighteen had been killed or wounded in the field and another had a grenade dropped on him in the shower. 

After a brief break-in period, Parks was sent out to the front lines, to an area where Highway 5A slithered out of the Vietcong-infested Delta like a black lizard. "The whole reason for the infantry being there," said Parks, "was to act as a checkpoint for the motor traffic coming out of the Delta headed for Saigon." Parks's weapon would be his DF device, a PRD-1, simply called the Purd. He kept it hidden from prying eyes, inside an octagonal tent. "Learning the Purd was not too difficult," Parks said. "Learning the ins and outs of staying alive was. . . . One learned to watch where to place each step as you walked, for there were snakes in the Delta that could kill you in seconds. The snakes of Vietnam were named according to how far a victim walked before dying from a bite, beginning with the 'three-pace snake,' the green krait, which had to chew its poison into you." Before turning in at night, Parks would take his bayonet and see what might have crawled into his bunk while he was at work. "Lizards mostly," said Parks, "but sometimes snakes, including the king cobra. We were in the Delta." 

There were many more rules to live by, according to Parks. "Don't pick up something without checking it for booby traps. Inside the bunker line, stay on the paths; outside of it, stay off of them. Don't venture outside the perimeter unless you were willing to die. Don't walk around at night inside the perimeter for danger of being shot by your own troops. There was plenty to learn and not much time to learn it." 

On a typical mission, the PRD-1 would be transported by jeep to what was thought to be a good spot from which to locate Vietcong in the Delta. Once at the site, a tactical DF post would be established. A bunker made of double or triple sandbags would be set up, then encircled with rolls of barbed wire and concertina wire, perhaps fifteen feet across. A variety of antennas would be set up and warning signs would be posted. "Signs telling," said Parks, "that this was a classified site and not to enter on pain of death and according to some regulation or another." In the center, sitting on a tripod, would be the PRD-1, which was about eighteen inches square and crowned with a diamond-shaped antenna that could be rotated. At its base was an azimuth ring marked off in degrees. 

Once he was set up, the DF operator would put on his earphones and begin listening for enemy signals. "Time to get on the knobs and kill a Commie for Mommy," said Parks. In order to cover the operational area, a "net" of three DF sites would have to be set up. This would allow the operators to triangulate the enemy signals and get a fix on their exact locations. " 'Find them, fix them, and fuck 'em over!' was our unofficial motto," said Parks. " 'Better Living Through Electronics' was another one." 

Once a DF station picked up an enemy transmission, the operator would take a bearing on it. The information would then be encrypted and sent up the chain of command and an attack order would frequently be given. Heavy artillery fire would then plaster the site, and the infantry would sweep in. 

Unfortunately, the Vietcong were wise to the game; they knew the United States was probably listening and they avoided transmitting as much as possible. Or they would place their transmitting antenna up to a mile from the actual transmitter, in order to avoid fire. "It was a great  and intricate game of fox and hounds played silently between us," said Parks. "Each side aware of the other though we never met. It was a life or-death game for them, too. To place it bluntly, the DF teams were there to aid the 199th in its task of killing those Vietnamese radio ops and all of their buddies, if at all possible. We hounded them unmercifully. . . . Their radio ops became worse as time went by due to the better-trained ones having been killed." 

But DF missions were a double-edged sword, as Specialist Davis had discovered. Since the range of the PRD-1 was only about five miles—on a very good day—the Sigint soldiers had to be almost in the enemy's camp to locate them. "They were practically in our lap most of the time," said Parks. "Once, we DF'd a transmission that was coming from a grass hut not three hundred yards from me—easy rifle shot if I could have caught him coming out of the hut." 

For Parks, the constant tension took its toll. "It was a rough way to live and work, and it took a lot out of men even as fit and young as we were," he recalled. "I'm not talking about the mission—I'm talking about being in that environment and doing everything it took to try and stay alive. I myself ended up in the hospital suffering from sheer exhaustion about three-quarters the way through my one-year tour. Truth is, I awoke in the 'hospital' after passing out cold one fine day. The 'hospital' was actually more like a ward on the upper floor of a barracks a block from the 856th. They needed to keep an eye on their own, you know— can't have me giving away any secrets in my delirium." 

By January 1968 NSA had placed Vietnam under a massive electronic microscope. Sigint specialists even scanned every North Vietnamese newspaper for pictures of communications equipment. Hardly a signal could escape capture by one of the agency's antennas, whether in a mud covered jeep slogging through the Mekong Delta or in the belly of a Blackbird flying sixteen miles over Hanoi at three times the speed of sound. Yet the signals were useless without adequate analysis, and analysis was useless if military commanders ignored it. 

A few years earlier the Joint Chiefs of Staff had calmly approved committing acts of terrorism against Americans in order to trick them into supporting a war they wanted against Cuba. Now that they finally had a war, the senior military leadership once again resorted to deceit— this time to keep that war going. Somehow they had to convince the public that they were winning when they were really losing. 

"If SD and SSD [both were Vietcong Self Defense forces—militia] are included in the overall enemy strength, the figure will total 420,000 to 431,000," General Creighton Abrams, the deputy U.S. commander in Vietnam, secretly cabled the chairman of the JCS in August 1967. "This  is in sharp contrast to the current overall strength figure of about 299,000 given to the press here. . . . We have been projecting an image of success over the recent months. . . . Now, when we release the figure of 420,000—431,000, the newsmen will . . . [draw] an erroneous and gloomy conclusion as to the meaning of the increase. ... In our view the strength figures for the SD and SSD should be omitted entirely from the enemy strength figures in the forthcoming NIE [CIA National Intelligence Estimate]." 

As intercept operators trolled for enemy communications, the results flowed back to NSA, where analysts deciphered, translated, and trafficanalyzed the massive amounts of data. Reports then went to the CIA and other consumers, including General Westmoreland's headquarters, the Military Assistance Command, Vietnam (MACV). Westmoreland's staff included NSA's Sigint reports in the command's highly classified publications, including the Weekly Intelligence Estimate Updates and the Daily Intelligence Summaries, both read by Westmoreland. Nevertheless, MACV refused to include any NSA data in its order-of-battle summaries, claiming that the information was too highly classified. 

There may have been another reason. NSA's Sigint was making it increasingly clear that enemy strength was far greater than the military commanders in Vietnam and the Pentagon were letting on, either publicly or in secret. CIA Director Richard Helms saw the difference between the estimates and told his top Vietnam adviser, George Carver, that "the Vietnam numbers game" would be played "with ever increasing heat and political overtones" during the year. To help resolve the problem, he asked analysts from the CIA, NSA, and the Defense Intelligence Agency to travel to Saigon and meet with General Westmoreland's staff to resolve the differences in numbers. 

The meeting took place in Saigon in September at the U.S. embassy. Over a conference table strewn with intercepts and secret reports, the Washington analysts attempted to make their case, but it was useless. Rather than rely on NSA's Sigint for enemy strength figures, the military instead relied on questionable prisoner interrogations. "MACV used mainly Confidential-level documents and prisoner interrogation reports," said a recent CIA study, "and, in contrast with CIA's practice, did not generally use data derived from intercepted enemy radio signals, or Sigint." 

George Carver, the lead CIA analyst at the meeting, expressed his anger in an "eyes-only" cable to Helms, characterizing the mission as "frustratingly unproductive since MACV stonewalling, obviously under orders." Despite the evidence, he said, Westmoreland's officers refused to accept any estimates of enemy forces larger than 298,000, and "the inescapable conclusion" must be drawn that Westmoreland "has given instructions tantamount to direct order that VC strength total will not  exceed 300,000 ceiling." He added that he was planning to see Westmoreland the next day and would "endeavor to loosen this straitjacket. Unless I can, we are wasting our time." 

In the end, the military refused to budge. Westmoreland's top military intelligence officer, Major General Phillip Davidson, told Carver to buzz off. "I was frequently and sometimes tendentiously interrupted by Davidson," Carver cabled Helms, "who angrily accused me of impugning his integrity," and who stated that the figures MACV had tabled were its "final offer, not subject to discussion. We should take or leave it." Eventually, caving in to the pressure, Carver and the CIA took it, greatly angering many of the other analysts. 

In November 1967, NSA began reporting that two North Vietnamese Army divisions and three regiments were heading toward South Vietnam. Follow-up reports continued over the next several months until the units arrived in South Vietnam, or in staging areas in the DMZ and Laos, in late 1967 and early 1968. 

Other reports began coming in January 1968 that a major attack was in the works. William E. Rowe, with the ASA's 856th Radio Research Detachment near Saigon, picked up intelligence that two Viet-cong regiments were planning to overrun the U.S. compound at Long Binh, Bien Hoa Air Base, and several other locations around the Saigon area. In addition to passing the information to NSA, the Sigint detachment "also told MACV headquarters personnel about reports of the planned attack on the Bien Hoa Air Base and several sites in Saigon such as the MACV headquarters building, the U.S. Embassy, the relay station, the radio station and the Phu Tho racetrack," said Rowe. "MACV headquarters personnel sloughed off the information. They ignored intelligence reports indicating the Vietcong were assembling in tunnels, caves, and foxholes." 

On January 17, NSA issued the first in a series of intelligence bulletins reviewing recent Sigint from Vietnam. It was likely, said the report, that NVA units were preparing to attack cities in Kontum, Pleiku, and Darlac provinces. Other attacks were being planned against the coastal provinces of Quang Nam, Quang Tin, Quang Ngai, and Bin Dihn. Still other intercepts indicated that Hue would be attacked. NSA reported that Sigint had also picked up indications of increased enemy presence near Saigon. 

Despite all these reports, the mood within Westmoreland's headquarters was upbeat, like the bridge on the Titanic. Although he was being warned that there were icebergs ahead, Westmoreland knew his massive ship was unsinkable. According to a recent CIA analysis, "A 'we are winning' consensus pretty much permeated the Saigon-Washington  command circuit; intelligence reports and analyses that deviated from it tended to be discounted." 

Off the coast of North Korea, the USS Pueblo was attacked on January 23, suddenly turning attention from the growing threat of a North Vietnamese invasion to the possibility of North Korean invasion. Many in the Johnson administration saw a connection. "It would seem to us that there is a relationship," said Westmoreland. Johnson and McNamara agreed. Nevertheless, there has never been any indication that the two events were in any way linked. 

Incredibly, despite the fact that NSA's Sigint warnings on Vietnam were becoming more and more alarming, the USS Oxford, NSA's premiere spy ship, was given permission to leave its station. On January 23, as North Korea captured the Pueblo and North Vietnam was on the verge of a major offensive, the Oxford sailed to Bangkok for a week of R&R. It was an enormous gaffe. 

The following day, NSA reaffirmed an earlier report that attacks against cities were imminent in northern and central South Vietnam. On January 25, NSA issued another alert, "Coordinated Vietnamese Communist Offensive Evidenced." The Sigint report gave clear evidence that a major attack was about to take place, citing an "almost unprecedented volume of urgent messages . . . passing among major enemy commands." The analysis went on to predict imminent coordinated attacks throughout all of South Vietnam, especially in the northern half of the country. Tet, the Vietnamese lunar New Year, was only five days off. 

Richard McCarthy also noticed unusual activity in the days before Tet. He was on a direction-finding patrol near the Cambodian border in his small RU-6A Beaver. Nearby was a large rubber plantation, Loc Ninh. "Evening missions were usually very quiet," he said. "The Americans were all lagging [sic] into their night defensive positions, and the VC were preparing for their night activities. This night was no exception. There was a large component of the 1st Infantry Division lagging in on the golf course at Loc Ninh, and I could see the smoke from white phosphorus, as smaller units around the area were setting in their final protective fires. 

"Suddenly I started picking up a familiar sound. I quickly identified the target as the reconnaissance element of the VC division that controlled the area. This was very unusual, because this guy usually didn't come on the scene until the last phases of planning an attack! When we finished the fix, we knew that we had something big. The target was located 300 yards outside of the American perimeter at Loc Ninh. We tried to contact the [ASA unit] at Loc Ninh, but they had shut down for the night. I elected to return to base and report that fix, instead of flying the full four hours that we were scheduled to fly." McCarthy later learned that his alert had thwarted one of the rehearsal attacks for the coming offensive. 

On January 30, Westmoreland finally saw the iceberg dead ahead. He had just been handed several warnings, based on Sigint, from the commander of the U.S. forces in the region around Saigon. The commander, Major General Frederick C. Weyand, had become convinced, by intercepts, traffic analysis, and DF indications he had just received, that a major offensive was about to take place. Westmoreland immediately canceled a previous Tet cease-fire he had issued and ordered that "effective immediately all forces will resume intensive operations, and troops will be placed on maximum alert." "These precautionary moves," said a recent CIA analysis, "doubtless saved Saigon and the U.S. presence there from disaster." 

That night Dave Parks noticed something very unusual. "At twelve midnight, the enemy went on total radio silence," he said. "It was just as if someone had switched off a light—'Nil More Heard' on any frequency. Now, that spooked the hell out of me. I had never experienced anything like it. Military units go on radio silence for only one reason: they're up to something. In this case they were on the move to their assigned targets." One of his colleagues, serving a second tour in Vietnam, told Parks, "If anything is going to happen it will happen at three A.M.— we may as well go and get some sleep." "He was dead on," said Parks, "we got the hell rocketed out of us at precisely three A.M. . . . What we didn't expect was the scale and intensity of the attacks." 

About the same hour, the 856th Radio Research Detachment at Long Binh, which weeks earlier had attempted to warn Westmoreland of the coming attack, came under bombardment. "They had been hiding in tunnels and foxholes in the area for about two weeks, awaiting orders from Hanoi," said William E. Rowe. "For the next two and a half hours the Vietcong initiated probing attacks against our bunker line and other positions along our perimeter. . . . Most of my buddies were in the operations building setting satchel charges and incendiary grenades to all the filing cabinets, equipment (radios and receivers), maps and reports—everything that should not fall into the hands of the enemy." 

It was a ferocious attack. "Each time they attacked," said Rowe, "some would get hung up in the wire. Each time they attacked, we went crazy, yelling expletives as we went out to meet them, firing and firing each time they approached. A mound of enemy dead was forming in front of the concertina, body upon body. The frontal attacks lasted for another two hours. After each advance, we would pace up and down the bunker line, nervously anticipating the next attack. After each attack, the mound of enemy dead got bigger and bigger."

As the fighting continued, Rowe's unit began running out of ammunition. "Those not swearing loudly were praying, preparing for close-in fighting. We knew if we did not get more ammunition, it would be a one-on-one struggle for each of us." The Sigint soldiers were ordered to hold their fire until the last instant, to preserve ammo. "When we could wait no longer," said Rowe, "we started to run toward the wire to meet them head on." A short while later, six helicopter gunships came to the rescue. Nevertheless, the ferocious battle went on for days. By the time it was over, enemy soldiers were stacked five deep around the listening post. "The plows pushed about four hundred dead Vietcong into a low drainage area to the right and in front of our bunker line." 

Gary Bright, a stocky, sandy-haired Army warrant officer, woke to the ring of the phone beside his bed in Saigon's Prince Hotel. It was 2:30 A.M. "They've hit the embassy and palace. The airfield is under attack," said the excited voice. "I'm going to blow the switch." The call was from a sergeant at NSA's newly installed Automatic Secure Voice Switch at the MACV compound on Tan Son Nhut Air Base. The switch was the key link for highly secret phone calls between Saigon and Washington, and the sergeant was afraid that the facility and all its crypto equipment would soon be captured. Bright, in charge of the switch, told the soldier to get ready for a destruct order but not to pull the plug before he arrived. 

Bright quickly threw on his tan uniform, grabbed his glasses, and ran down three flights of stairs to his jeep. "As we got in I armed my grease gun—a .45-caliber submachine gun—and watched the street," he said. Bright and his partner sped down Plantation Road, the main traffic artery, toward the MACV compound. As they rounded the traffic circle near the French racetrack they passed another jeep with its lights on. Seconds later Bright heard a loud explosion and turned around to see the second jeep demolished and in flames. Then he started taking fire from the top of the racetrack wall, bullets crashing into his vehicle. Bright swiveled around and opened fire with his submachine gun, knocking some of the Vietcong shooters off the wall. 

Upon reaching the secure switch, Bright began to prepare for emergency destruction. Later a call came in from the U.S. embassy. "The VC were on the first floor," Bright said. The caller was shouting, worried that enemy forces would soon capture the sensitive communications and crypto equipment. To make matters worse, the embassy had no destruct devices and Bright was asked to bring some over. "I got on the phone and told them that it was impossible to get out, much less get downtown to them," Bright recalled. "I told them the best thing to do was to shoot the equipment and smash the boards as much as possible if emergency destruction became necessary." 

At the time of the attack, the Oxford's crew was living it up in Bangkok. The ship would not sail back until February 1, a day after the  start of the biggest offensive of the war. 

Battles were taking place simultaneously throughout South Vietnam, from Hue in the north to Saigon in the south. By the time the acrid cloud of gunsmoke began to dissipate, on February 13, 4,000 American troops had been killed along with 5,000 South Vietnamese and 58,000 North Vietnamese soldiers. Although the United States eventually turned back the Tet offensive, the American public now realized what price was being paid for a war without end. 

The sole winner to come out of Tet was NSA. Of all the intelligence agencies, it was the only one to come up with the right warning at the right time. That the intelligence was not acted on much sooner was the fault of Westmoreland and the generals and politicians in Saigon and Washington who refused to pay attention to anything that might detract from their upbeat version of the war and their fantasy numbers. "The National Security Agency stood alone in providing the kind of warnings the U.S. Intelligence Community was designed to provide," concluded a 1998 CIA review of the war, which gave only mediocre reviews to the agency's own intelligence. "Communications intelligence often afforded a better reading of the enemy's strength and intentions (and was better heeded by command elements) than did agent reports, prisoner interrogations, captured documents, or the analytic conclusions derived from them. But in Washington the Sigint alerts apparently made little impression on senior intelligence officers and policymakers." 

Finally, the CIA study concluded, "Senior intelligence and policymaking officers and military leaders erred on two principal scores: for having let concern for possible political embarrassment derail objective assessments of the enemy order of battle, and for ignoring NSA's alerts and Saigon Station's warnings that did not accord with their previous evaluations of probable enemy strategy." 

Pleased with his agency's performance, Director Marshall S. Carter, on May 8, 1968, sent a telegram to former president Harry S. Truman on his eighty-fourth birthday. "The National Security Agency extends its heartiest congratulations and warm wishes," he wrote. "You will recall establishing the National Security Agency in 1952 and we will continue to strive to accomplish the objectives you laid down for us at that time." 

Back in Washington, Lyndon Johnson was being compared in the press to General George Custer at the Battle of the Little Big Horn. About a month after the heavy fighting ended, he announced he would no longer be a candidate in the upcoming presidential election. In Vietnam, American troops suddenly began to realize they might be fighting a losing war. 

Some soldiers who physically survived Tet nevertheless died inside. Following one fight, an injured American soldier and two wounded  Vietcong were brought to an aid station at a firebase named Stephanie. After attempting, unsuccessfully, to save the U.S. soldier, an Army medic went off to have a beer while leaving the two Vietcong, a father and his young son, to bleed to death. 

Nearby was Dave Parks, working his PRD-1 direction finder. "Nothing had been done to attend to their wounds," he said. "The younger one, despite having several chest wounds and his left leg shot nearly in two below the knee, was alert; we looked into one another's eyes as I paused briefly to look them over. There was fear in the eyes, and pain. The older fellow was pretty far gone. His eyes were glazed over and half closed. . . . Without help they were not going to live. Even my untrained eye could see that." 

Parks returned to his direction finder, expecting that the medic would treat the men. But a short while later he looked back and saw they had never been attended to. "I got up and went over to them, expecting to find them dead," he said. "The older fellow was dead now, his eyes filmed over but still open in death. The young one was alive but not nearly as alert as before; his dark eyes briefly locked into mine when I approached. I felt the need to do something for him; it looked as if the medic had forgotten these two." Returning to his DF site, Parks grabbed a canteen to give the young Vietcong some water, but first thought he would check with the medic to see if water was the right thing to give him. "I wondered why nothing was being done . . . ," said Parks. "I found the medic inside the bunker drinking a warm beer and asked him what would be done with the VC, adding that one looked as if he was already dead. 'Fuck those gooks,' he swore at me, voice rising. 'Leave them the fuck alone, they can just hurry up and die 'cause I'm not touchin' those filthy bastards!' " Confused by the medic's reaction, Parks returned to the injured boy. "The sergeant had done a good job of intimidating me into doing nothing," he said, "but I was still left with the feeling that I should try something. 

"Looking down on the VC," Parks continued, "it dawned on me that the medic knew full well their situation. He was allowing them to die; it was his payment to the dead American. I spent a moment or two looking at the young VC. His eyes seemed duller now, and the flies were all over his wounds. I knelt beside him and brushed at the flies to no real effect. 'Screw him,' I thought, thinking of the medic. I pulled the stretcher into the shade. I ripped a square off of the old fellow's shirt and wet it from my canteen. I wiped the teenager's forehead, upper chest, and arms." 

Parks attempted to get the help of a nearby Army captain. " 'Sir, one of the VC that came in with that kid is still alive. He looks like he's going to die if something isn't done. The sergeant says he won't touch him.' The captain looked at me, looked over toward the aid station, and back at me. 285 He said, 'If I were you, Specialist, I'd keep my goddamned nose out of it. The sergeant is in charge over there, and you just might need his services someday. Let him run the aid station any damned way he sees fit!' 

"Not the answer I had expected. The subtext of the man's statement was clear enough, though. The good captain just might need the sergeant's services someday, too, and he wasn't about to screw with that. Defeated, I returned to my war, and my area of responsibility in it. By sundown the young VC was dead. "I have lived with that day's events for thirty-plus years now, I am positive I will live with them for the rest of my life. . . . The Vietcong teenager is my personal guilt. I should have moved heaven and earth to do more for him, but I failed him." 

Following the Tet offensive, the war, like the young Vietcong, slowly began to die. The next year, NSA pulled its Sigint ships from Vietnam and then scrapped the whole fleet. "My opinion of 1969 on Oxford thirty years later," said Richard E. Kerr, Jr., "[is that] we proved to the NSG [Naval Security Group] Command and the CNO [Chief of Naval Operations] that operations like this at sea . . . were obsolete. You cannot combine large numbers of NSG personnel with uncleared officers and crew. All the ships . . . were too slow, too old, and had no business being in tense situations. . . . Events of the Liberty and Pueblo (1967 and 1968) had already placed this type of platform in jeopardy. Vietnam was over in 1968 and the [Sigint] fleet was dead in 1969." 

By then, largely as a result of the war in Vietnam, NSA's cryptologic community had grown to a whopping 95,000 people, almost five times the size of the CIA. In Southeast Asia alone, NSA had over 10,000 analysts and intercept operators. In addition, the agency's budget had grown so large that even Carter called it "monstrous." To emphasize the point, one day the director called into his office an employee from the NSA printing division who happened to moonlight as a jockey at nearby Laurel racetrack. The man stood about four feet six. Carter had the jockey get behind a pushcart, on which the budget documents were piled high, and called in the NSA photographer to snap the picture. The photo, according to Carter, was worth a thousand explanations, especially since "you couldn't tell whether [the jockey] was four feet six or six feet four." 

On the last day of July 1969, Carter retired after presiding over the bloodiest four years in the agency's history. In a letter to a friend, he had harsh words for the middle-level civilians at the Pentagon who, he complained, were trying to micromanage NSA through control of his budget. He called them "bureaucrats at the termite level." Carter had also become anathema to many on the Joint Chiefs of Staff for his independence, for example in the matter of Vietcong numbers.

In a revealing letter to his old boss at CIA, former director John McCone, Carter explained some of his troubles. "I am not winning," he said, "(nor am I trying to win) any popularity contests with the military establishment nor those civilian levels in the Pentagon who have a testicular grip on my acquisition of resources. For all my years of service, I have called the shots exactly as I have seen them. I am hopeful that the new administration [Nixon's] will try to overcome some of this and leave the authority where the responsibility is. The usurpation of authority at lower staff levels without concomitant acceptance of responsibility is the main problem that somehow must be overcome by the new administration. I tell you this in complete privacy after almost four years in this job. I would not wish to be repeated or quoted in any arena." 

Picked to become the sixth NSA director was Vice Admiral Noel Gayler, a handsome, salt-and-pepper-haired naval aviator. Born on Christmas Day, 1914, in Birmingham, Alabama, Gayler graduated from the Naval Academy and spent the better part of his career as a fighter pilot. In many respects, Gayler's background was the exact opposite of Carter's, which may have been the reason he was chosen. Whereas Carter had been influenced by civilian attitudes during tours at the State Department and the CIA, Gayler's background was virtually untouched by civilian influence. Also, his lack of prior intelligence experience may have been seen as an advantage by those who felt Carter had tried to turn NSA into another CIA. Finally, unlike Carter, who knew he was on his final tour and therefore could not be intimidated very easily, Gayler was young enough to have at least one more assignment ahead of him, which could earn him a fourth star. He could be expected, then, to toe the line when it came to military versus civilian decisions. 

If those were the reasons behind Gayler's selection, it seems that, at least initially, the planners must have been disappointed. Within two years, the Army was complaining that Gayler, like Carter, had traitorously turned his back on the military and was making NSA more civilian than ever. In October 1971 the chief of the Army Security Agency, Major General Charles J. Denholm, told his tale of woe at a classified briefing for the Army vice chief of staff. 

"At the end of World War II," Denholm told General Bruce Palmer, Jr., "NSA was about 99 percent military. Now at NSA within the top two thousand spaces, you will find that there are perhaps five percent military. . . . There are about thirteen military men among the three services out of about 275 supergrades [a supergrade is the civilian equivalent of an Army general] that are running the show. So the military has gradually disappeared from the higher echelons at NSA." Denholm concluded, in the not-for-NSA's-ears briefing, "I fear that in about five years there probably will be no more military at NSA. All the key NSA slots are disappearing." 

By the early 1970s, with the war in Vietnam winding down, the war within NSA for control of the dwindling budget heated up. The question was whether the civilians or the military would be in charge of the vault. In what one former NSA official termed a "declaration of war," a strategy paper was submitted to Director Gayler, arguing that that person should be a civilian. 

The paper was co-written by Milton S. Zaslow, then the assistant deputy director for operations and the second most powerful civilian in the agency. It argued that because the civilian leadership at NSA represent continuity, civilians were in a better position to determine the needs of the Sigint community. Said the former NSA official quoted above: "The strategy paper was written saying, 'We're the ones who know all about this stuff, we'll control it and we'll tell you what you can have, and we'll see that you get the support you need when you need it.' " 

But the military side argued that since it operated the listening posts, the aircraft, and the submarines, it should have final authority over the budget. 

Eventually Gayler had to make the choice—and the decision went to the military. In the view of one of the civilians: "He wasn't a ballplayer until the end. From what I saw, he [Gayler] was really good for NSA, up until the end, and then I think he sold out; he went along with the military." Whatever his motive, Gayler's move was handsomely rewarded by the Joint Chiefs of Staff. On August 24, 1972, after three years as America's chief electronic spymaster, he was promoted to full admiral and awarded one of the choicest assignments in the military: Commander-in-Chief, Pacific (CINCPAC), based in Hawaii. Gayler's ascent to four-star rank and promotion to bigger and better things marked a turning point in the history of the NSA. Before Gayler, the NSA directorship was generally acknowledged to be a final resting place, a dead-end job from which there was no return. Beginning with Gayler, however, NSA frequently became a springboard to four-star rank and major military assignments. 

Gayler's successor was Lieutenant General Samuel C. Phillips, an Air Force officer who, while seconded to NASA, directed the Apollo space program from its infancy through the lunar landing in 1969. By the time Phillips arrived at NSA, in August 1972, American fighter pilots in Vietnam were being shot down in ever increasing numbers. Earlier, NSA had succeeded in intercepting a weak beacon transponder signal transmitted from a small spiral antenna on the tail of the Soviet 288 SA-2 surface-to-air missile. This antenna transmitted the SA-2's navigational data back to the launch site. "It came on thirty seconds after the missile's launch," said one former NSA official, "so that the launch site can track the missile and steer it close enough to where its own homing system will lock on to the target and go in for the final kill." 

Once such a signal had been captured and dissected by NSA, however, technicians were able to secretly jam the signal, sending the missiles off course and saving the lives of hundreds of pilots. But in 1972 the North Vietnamese realized something was very wrong and called in the Soviets to help correct the problem. Shortly thereafter the frequencies were changed and the SA-2 missiles once again began hitting their mark. 

Despite months of effort, intercept operators were not able to recapture the faint signal. Then, in late 1972, someone at NSA headquarters recalled a pet project by a Navy cryptologic officer. Using spare, off-the-shelf equipment, he had put together a unique signal acquisition system. Within twenty-four hours, the officer, John Arnold, was sent off to Southeast Asia with his experimental machine and assigned to the USS Long Beach. Arnold's machine worked better than anyone could have anticipated. Once again, they were able to intercept the elusive SA-2 signal, and the hit-kill ratio switched back to America's favor. "They dumped more than a million dollars in other systems and platforms trying to find the answer and they couldn't," said Arnold. 

By 1972, NSA also began "remoting" some of its more hazardous operations. Rather than having intercept operators sit in front of row after row of receivers, spinning dials to find enemy voices, now the agency could do much of its eavesdropping by computer. 

Codenamed Explorer, the system involved preprogrammed computers and receivers that would quickly scan for targeted and unusual frequencies carrying voice and coded communications. Once located, they would be uplinked to an aircraft or satellite and then, through a series of relays, downlinked to NSA or some other safe location away from the fighting. There, translators, codebreakers, computers, and traffic analysts could dissect the signals. A similar system, codenamed Guardrail, was established in Europe. In Guardrail, an aircraft was used as a relay to move Sigint from the front lines to analysts in the rear. 

Explorer was particularly useful in unusually dangerous areas— for example, just south of the DMZ. To capture those communications, the system was set up on several remote firebases located on high and isolated hills. One was Firebase Sarge and another was known as A-4. Although Explorer was highly automated, several people were nevertheless needed to maintain the equipment and keep it from being vandalized, a very hazardous job given the locations. 

The firebases just south of the DMZ were the most isolated and  dangerous listening posts in the world. There, intercept operators were close enough to the dragon to count its teeth. Occasionally they would also feel its sting. A-4 sat on the top of a steep mountain near Con Thien. "From A-4 you could see the middle of the DMZ, it was that close," said an intercept operator stationed there. "It was the furthest northernmost outpost the Americans held in Vietnam. The DMZ looked like rolling hills; a no-man's-land with a river through it and scrub brush and that was about it for miles. There was no fence. The river separated it and over the river was a bridge and the NVA flew a big flag over it with a red star and you could see it through binoculars. We used to watch them infiltrate, you could watch them come across. At the time there were no other Americans there." 

Working in a tiny underground bunker, the handful of intercept operators pinpointed enemy infiltrators, artillery units moving toward the border, and mobile surface-to-air missiles through voice and coded intercepts. "In A-4 we were in a bunker underground," said the intercept operator. "They had the codes broken, they could pick up the firing designators. When the North Vietnamese got on the radio to open up the guns or the rocket attack, they would use designators. And the Americans knew the designators, so we would know when we were about to get shelled and we would go back underground so we didn't get blown up." 

The concrete bunker was about ten feet underground and held only about five to seven intercept operators. Five worked the intercept equipment while the other two slept. They would take turns and they were all volunteers. Nearby was another bunker containing the NSA Explorer remote intercept equipment. In early 1972, the intercept operators at A-4 began getting indications of something larger than the usual infiltration or harassment taking place across the border. "We thought there was going to be an invasion, and nobody was really listening," said one intercept operator who was there at the time. "That was January, February, beginning of March 1972. There was just too much buildup of activity above the DMZ for it not to happen. We were reporting that to the higher-ups. But in my personal opinion, it fell on deaf ears because at that time there weren't any Americans except for the intelligence people and then the few American advisers who were up there." 

Further to the west, at Firebase Sarge, indications of a major attack were also becoming more numerous. There, the only Sigint personnel were two Army specialists, Bruce Crosby, Jr., and Gary Westcott, assigned to maintain the Explorer equipment contained in a bunker. The only other American was Marine Major Walter Boomer, who was an adviser to South Vietnamese forces assigned to the firebase. Earlier in March, Boomer had warned General Giai, the commanding general of the  South Vietnamese Army's 3rd Division, of his deep concern about the steady increase in enemy activity in the area. He told Giai that he felt that something significant was going to take place soon. The general listened but said there was little he could do. 

To the south, at Cam Lo, a secret American facility monitored the DMZ through ground-surveillance devices planted throughout the zone. During most of March, the number of trucks detected crossing the DMZ had tripled, and the monitors recorded both wheeled and tracked vehicle traffic, a worrisome sign. By the end of the month, the monitors were recording heavy traffic even during daylight hours, something that had never happened before. 

The bad news came on Good Friday, March 30, 1972. Just before noon on Firebase Sarge, Major Boomer passed on to his headquarters some disturbing news. "Shortly after daylight the NVA began to shell us here at Sarge," he said. "The NVA's fire is as accurate and as heavy as we have ever experienced up here. We're all okay now, but there is probably a big battle coming our way. ... It looks like this could be their big push." 

It was Tet all over again. The North Vietnamese Army had launched their largest offensive in four years, and U.S. and South Vietnamese forces were just as unprepared as they had been the last time. In fact, the U.S. military command in Saigon, 350 miles south, refused to believe a major attack was in progress even after it had begun. Over 30,000 wellarmed soldiers supported by more than 400 armored fighting vehicles, tanks, mobile missile launchers, and long-range cannons poured over the DMZ. Crossing the Ben Hai River, they knifed into the South's Quang Tri Province and turned the lonely firebases, like islands in the sky, into shooting galleries. 

Up on Firebase Sarge, as the earth rolled from the violent assault, Boomer ordered Westcott and Crosby to remain in the NSA Explorer bunker and keep in radio contact with him and also with the listening post at A-4. Explorer was housed in an aluminum hut that also contained eight pieces of NSA crypto equipment. Around the hut was a bunker made of several rows of sandbags and a steel roof covered with another five feet of additional sandbags. For ventilation there was a window on one side. 

Below Sarge, Soviet 130mm guns, the size of telephone poles, let loose with boulderlike shells. The rattle of small-arms fire followed and then the heavy crump of 122mm rockets raining down. Suddenly both A-4 and Boomer lost contact with Westcott and Crosby. Shortly after noon, a rocket scored a direct hit, crashing through the window in the NSA Explorer bunker. The two intercept operators were killed instantly and the bunker became a crematorium, burning for days. More than a decade after the first Sigint soldier died in Vietnam, two of the last were killed.

With A-4 also under heavy assault, the intercept operators were ordered to begin destroying Explorer and the rest of the crypto equipment and files. Above each of the sensitive devices were thermite plates for quick destruction. The plates were electrically activated and were wired together to a switch on the outside of the hut. Each thermite plate— about a foot wide and an inch thick—was designed to burn at the solar-like temperature of 35,000 degrees Fahrenheit. "The hut would burn for a couple of days before all the metal essentially turned to ash," said one of the soldiers who installed the destruction devices. "Once the thermites reached full temperature and the hut started burning no one could possibly survive and in the end there would be nothing left, absolutely nothing." Within a day of what became known as the Easter Offensive, there was no evidence that NSA had ever been at A-4, just ashes. The war was over and the United States had lost. 

On January 27, 1973, the United States and Vietnam signed a ceasefire agreement. At 7:45 A.M., fifteen minutes before the cease-fire took effect, the USS Turner Joy, which had helped launch America's misguided adventure, sailed off the Cam Lo—Cua Viet River outlet and senselessly fired off the last salvo of the war. 

Six months later, after barely a year in office, Samuel Phillips left NSA to head up the Air Force Space and Missile Organization. The man chosen to finish out his assignment was Lieutenant General Lew Allen, Jr. Tall and professorial-looking, with rimless glasses and a few wisps of fine dark hair across his crown, Allen, an expert in space reconnaissance, arrived at NSA following an assignment of only five and a half months with the CIA. 

The new director arrived in time to watch events in Vietnam rapidly deteriorate. By 1975 American troops were out of the country and the Communist forces in the north were pushing south in an effort to finally consolidate the nation and their power. Their secret goal was to capture Saigon by May 19, the birthday of Ho Chi Minh, who had died in 1969, at the age of seventy-nine. 

By April the endgame was near. At four o'clock on the morning of April 29, Saigon woke to the sound of distant thunder: heavy artillery fire on the outskirts of the city. Residents broke out in panic. Any hope that the U.S. Embassy staff and remaining Americans would be able to conduct a somewhat dignified departure by aircraft was dashed when explosions tore apart the runways at Tan Son Nhut Air Base. The only thing left was Operation Frequent Wind, the emergency evacuation by helicopter. 

Two hours after the NVA arrived in the outskirts of Saigon, at 6:10 A.M., NSA's national cryptologic representative there signed off for the  last time. "Have just received word to evacuate," he wrote in his Secret/Comint Channels Only message, "exclusive" for Lew Allen. "Am now destroying remaining classified material. Will cease transmissions immediately after this message. We're tired but otherwise all right. Looks like the battle for Saigon is on for real. ... I commend to you my people who deserve the best NSA can give them for what they have been through, but essentially for what they have achieved." Four days earlier, NSA's operations chief in Saigon, Ralph Adams, had been ordered out. "I took the last fixed-wing aircraft out of Saigon," he recalled. "Don't ever want to do that again. I watched an entire nation just crumble. It was scary as hell." 

In the sullen heat, the repeated sounds of "White Christmas" over the military radio station was surreal, as it was supposed to be. It was the signal for the last Americans to quickly get to their designated removal points. The U.S. embassy suddenly became a scene out of Dante. Mobs of Vietnamese, including many who had cooperated with the United States and had been promised evacuation, stormed the walls and pushed against the gate. A conga line of helicopters took turns landing on the embassy's roof, their blades barely slowing. Americans and Vietnamese relatives and helpers ducked low and climbed on board to be whisked away to an American naval flotilla in the South China Sea. Other choppers, flown by escaping South Vietnamese pilots, made one-way flights to the flattops and were then pushed into the sea, like dead insects, to make room for more rescue aircraft. 

Largely deaf as to what was going on fifty miles away in Saigon, the commander of the flotilla asked NSA to lend him an ear. A short time later an intercept operator tuned in on the embassy's communications and continuously recounted events, minute by minute, to the flotilla. With the beginning of Operation Comout, NSA, the ultimate voyeur, secretly began eavesdropping on the final agonizing gasps of the Vietnam War. 

At 7:11 P.M. the NSA intercept operator reported: 

THEY CANNOT GET THE AMBASSADOR OUT DUE TO A FIRE ON TOP OF THE EMBASSY. CINCPAC [Commander-in Chief, Pacific] REPORTED THEY CANNOT CONTINUE THE EVACUATION PAST 2300 [11:00 P.M.] LOCAL AND IT IS IMPERATIVE TO GET ALL OF THE AMERICANS OUT. 

Ambassador Graham Martin sat in his third-floor office, his face ashen as his diplomatic post crumbled around him. Henry Boudreau, an embassy counselor, walked in and was taken aback. "I saw the ambassador briefly and was startled at how hoarse he was, how barely able to speak. The pneumonia had all but wiped him out." 

Earlier that morning his black, bulletproof Chevrolet limousine had carried him to the U.S. compound, still in a state of disbelief. For weeks, as the North Vietnamese Army closed in on Saigon, Martin had refused to accept the inevitable. He believed that a face-saving exit was still possible. "Goddamnit, Graham!" shouted a frustrated Washington official in Saigon to help with the evacuation. "Don't you realize what's happening?" Drifting in from the hallways was the bitter scent of smoke from incinerators crammed too full of thick files and endless reports. By now, desperate Vietnamese were camped in every part of the embassy, their life's belongings held in torn paper bags. Children with puffy cheeks and frightened eyes clung tightly to their mothers' long ao dais. 

NSA: 7:13 PM 
NO AMBASSADOR [present]. THERE ARE STILL MANY U.S. PERSONNEL AT THE EMBASSY. 

Martin had insisted that Americans not be given preferential treatment over Vietnamese in the evacuation, but this rule, like most, was ignored as U.S. officials pushed to the head of the line. 

NSA:11:28PM 
THE AMBASSADOR WILL NOT, RPT NOT LEAVE UNTIL THERE ARE NO MORE PERSONNEL TO BE EVACUATED. HE STATES THAT ALL PERSONNEL WITHIN THE COMPOUND ARE EVACUEES. 

The roof of the embassy was a horror. The scream of helicopter blades drowned out voices, the gale-force prop blast scattered straw hats and precious satchels into the dark night, and flashing red under-lights and blinding spot beams disoriented the few lucky enough to have made it that far. 

In Washington it was 11:28 A.M., half a day earlier. Senior officials, including Secretary of State Henry Kissinger, were becoming impatient. A news conference had been scheduled to advise the press on the smooth and skillful evacuation. 

NSA: 2:07 AM, APRIL 30 
A PRESIDENTIAL MSG IS BEING PASSED AT THIS TIME. THE GIST OF THE MESSAGE . . . WAS THAT THE AMBASSADOR WAS TO EVACUATE NO MORE REFUGEES AND WAS TO GET ON THE LAST CHOPPER HIMSELF. 

Given an absolute deadline of 3:45 A.M., Martin pleaded for six more choppers as embassy communications personnel smashed the crypto gear with sledgehammers. Three miles away, fighting had broken out at Tan Son Nhut Air Base. The muffled sounds of cannon fire and the flash of rockets seemed a distant fireworks display. NSA: 

3:43 AM 
LADY ACE 09 [the helicopter for the ambassador] IS NOT TO PICK UP ANY PAX [passengers] UNTIL HE HAS AGAIN RELAYED THE PRESIDENTIAL ORDER TO THE AMBASSADOR. THE ORDER IS THAT THERE ARE ONLY 20 ACFT [aircraft] REMAINING AND ONLY AMERICANS ARE TO BE EVACUATED. 

Martin missed the deadline and was pressing for still more choppers for both Vietnamese and Americans. But now Washington and Pacific Command in Hawaii were ordering that no more Vietnamese be allowed on the aircraft. At the same time the Communists were almost on the embassy's doorstep. 

NSA: 3:51 AM 
LADY ACE 09 IS ON THE ROOF WITH INSTRUCTIONS ONLY TO PICK UP AMERICANS. 

NSA: 3:52 AM 
THERE HAS BEEN AN SA-7 [surface-to-air missile] LAUNCH 1 MILE EAST OF TAN SON NHUT. 

As hundreds of Vietnamese still covered the embassy grounds, recalled Frank Snepp, a CIA official who remained to the end, a Marine major marched into Martin's office and made an announcement at the top of his voice. "President Ford has directed that the ambassador leave by the next chopper from the roof!" the Marine said. Martin, his face pasty white and his eyes swollen from exhaustion, lifted his suitcase. "Looks like this is it," he said to several others in the room, the finality of 295 the situation at last washing over him. On the roof, Kenneth Moorefield, the ambassador's aide, escorted Martin through the muggy darkness to the door of Lady Ace. "As I lifted him through the door of the helicopter," Moorefield recalled, "he seemed . . . frail, so terribly frail." 

NSA: 3:58 AM 
LADY ACE 09 IS TIGER TIGER TIGER. THAT IS TO SAY HE HAS THE AMBASSADOR OUT. 

The assurances given Martin that six more choppers would be sent for the remaining Vietnamese were a lie. The White House ordered that only the remaining Americans would be evacuated. 

NSA: 4:09 AM 
THERE ARE 200 AMERICANS LEFT TO EVAC. . . . BRING UR [your] PERSONNEL UP THROUGH TH [the] BUILDING. DO NOT LET THEM (THE SOUTH VIETS) FOLLOW TOO CLOSELY. USE MACE IF NECESSARY BUT DO NOT FIRE ON THEM. 

As choppers swooped in and picked up the final Americans, the gunfire began getting closer. 

NSA: 4:42 AM 
NUMEROUS FIRE FIGHTS ALL AROUND THE BUILDING. 

NSA: 5:03 AM 
AAA [anti-aircraft artillery] EMPLACEMENT ABOUT SIX BLOCKS WEST OF EMBASSY HAS BEEN CONFIRMED. 

NSA: 5:25 AM 
ALL OF THE REMAINING AMERICAN PERSONNEL ARE ON THE ROOF AT THIS TIME AND VIETNAMESE ARE IN THE BUILDING. 

NSA: 5:48 AM 
296 SOUTH VIETNAMESE HAD BROKEN INTO THE EMBASSY BUT WERE JUST RUMMAGING AROUND AND NO HOSTILE ACTS WERE NOTED.

NSA: 6:18 AM 
LADY ACE IS ON THE ROOF. HE STATES THAT HE WILL LOAD 25 PAX AND THAT THIS WILL LEAVE 45 REMAINING HENCE THEY NEED MORE CHOPPERS. 

NSA: 6:51 AM 
SWIFT 22 IS OUTBOUND WITH 11 PAX ON BOARD INCLUDING THE LZ [landing zone] COMMANDER. ALL THE AMERICANS ARE OUT REPEAT OUT. 

Within a few hours, Saigon had been taken over and renamed Ho Chi Minh City. But while the departing embassy employees left only ashes and smashed crypto equipment for the incoming Communists, NSA had left the NVA a prize beyond their wildest dreams. According to NSA documents obtained for Body of Secrets, among the booty discovered by the North Vietnamese was an entire warehouse overflowing with NSA's most important cryptographic machines and other supersensitive code and cipher materials, all in pristine condition—and all no doubt shared with the Russians and possibly also the Chinese. Still not admitted by NSA, this was the largest compromise of highly secret coding equipment and materials in U.S. history. 

In early 1975, as it began looking more and more as if South Vietnam would fall, NSA became very worried about the sensitive crypto machines it had supplied to the South Vietnamese government. 

In 1970, the NSA had decided to provide the South Vietnamese military with hundreds of the agency's most important crypto devices, the KY-8 and the NESTOR voice encryption machines. NSA officials provided strict warnings not to examine the equipment's workings. Nevertheless, officials later believed that the South Vietnamese did open and examine some of the machines. By late 1974 and early 1975, with the military situation not looking good, the agency decided to try to get the machines back from the South Vietnamese government to prevent them from falling into the hands of the enemy. "Delicate political moves were made to keep from offending the RVN [Republic of Vietnam] general staff," said one official involved. 

By January and February 1975, according to the official, "it was determined that the situation was becoming critical." Stepped-up efforts were made to remove the machines to the South Vietnamese National Cryptographic Depot (known as Don Vi’ 600) at Tan Son Nhut Air Base. The depot was located next to the U.S. Armed Forces Courier Service station, which was to transport the crypto machines back to NSA. 

But things went terribly wrong. "In the last three weeks of the existence of the Republic of Vietnam," wrote the official, "some 700 pieces of ADONIS and NESTOR [encryption] equipment had been gathered and prepared for shipment to CONUS [Continental U.S.]. Unfortunately, none of this equipment was shipped or destroyed. None of the facility or its contents were destroyed. It was estimated that enough keying material and codes were abandoned for 12 months full operation of the on-line, off-line, and low-level codes in country." 

It was a compromise of enormous magnitude. Officials may have felt that although the Russians no doubt obtained the crypto machines from the Vietnamese, they still needed the keylists and key cards. What the United States would not know for another decade was that John Walker was secretly selling current keying materials to the USSR. Even if NSA decided to make some changes to the machine, Walker would get a copy and simply hand it over to the Russians. NSA has kept the embarrassing loss of the crypto materials secret for decades. 

next 
CHAPTER TEN 
FAT
 

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