The Tet Offensive
Dialogues
April 2004
by: Steven Hayward
This article was excerpted from Steven F.Hayward’s book, The Age of Reagan: The Fall of the Liberal Order, 1964-1980.
On January 5th, the Joint United States Public Affairs Office in Saigon released to reporters the contents of a Viet Cong soldier’s notebook that had fallen into the hands of U.S. intelligence two months before. The key passage read:
"The central headquarters has ordered the entire army and people of South Vietnam to implement general offensive and general uprising in order to achieve a decisive victory. . . Use very strong military attacks in coordination with the uprisings of the local population to take over towns and cities. Troops should flood the lowlands. They should move toward liberating the capital city [Saigon], take power and try to rally enemy brigades and regiments to our side one by one. Propaganda should be broadly disseminated among the population in general, and leaflets should be used to reach enemy officers and enlisted personnel."1
Because the VC soldier’s notebook had been captured up near the De-Militarized Zone (DMZ), not far from where North Vietnamese troops were thought to be massing for an attack on the U.S. base at Khe Sanh, U.S. intelligence dismissed the contents of the notebook as disinformation, as a means of diverting attention away from where the main blow was expected to fall. Hence it received little emphasis by U.S. military commanders in Saigon, and little notice in the news media. This was merely one of the countless missed signals contributing to what Army General Bruce Palmer later called "an allied intelligence failure ranking with Pearl Harbor in 1941"—the surprise of the Tet offensive.2
On January 30, in the middle of the Tet new year holiday, North Vietnamese regular army troops and Viet Cong troops struck in a coordinated attack on 36 of South Vietnam’s 44 provincial capitals, and 70 other towns in the country. The North Vietnamese also unleashed a ferocious attack on the U.S. base at Khe Sanh that lasted two months. The North Vietnamese stormed the coastal city of Hue; it required some of the hardest fighting of the war over the next month for U.S. Marines to retake the city. The most stunning blow of the surprise attack was the guerrilla raid on the U.S. embassy in downtown Saigon. Nineteen Viet Cong commandos blasted a hole in the perimeter wall of the embassy compound at 3 a.m., and killed five U.S. GIs upon storming the embassy grounds. (Four South Vietnamese policemen assigned to guard the embassy fled when the shooting started.) U.S. forces killed all of the commandos within a few hours, but the episode, occurring amidst an unexpected and widespread offensive, was a severe embarrassment for the U.S.
The Tet offensive proved to be the turning point of the war, delivering a fatal blow to political support for the war in the United States. Even though Tet was a disappointing defeat for North Vietnam in strictly military terms, it exposed the bankruptcy of U.S. war policy and aims in Vietnam, and prepared the way for America’s eventual humiliation. The most surprising aspect of the Tet offensive was that it was not really a surprise at all. Yet the episode shows how even a superior force can be taken by surprise both militarily and politically when it lacks the initiative in war. Since the North Vietnamese had the initiative instead of the U.S., it was possible for their elaborate campaign of deception to succeed in maintaining the element of surprise, even though the U.S. discovered numerous details of the attack to come.
The complete battle plan for the Tet offensive has never been revealed, but it is evident that the plan for a major offensive against South Vietnam originated in the summer of 1967, following the death of North Vietnamese General Nguyen Chi Thanh. (Thanh is thought to have been killed in an American bombing raid in Cambodia, though rumors of assassination—which might have been disinformation—made the rounds.) North Vietnam used the cover of Thanh’s funeral to recall its diplomatic corps to Hanoi for consultations. This was the first signal that U.S. intelligence missed. U.S. analysts assumed that the diplomatic recall was purely for the purpose of attending Thanh’s funeral, forgetting that the only previous time such a wholesale diplomatic recall had taken place was immediately after the U.S. had committed its first ground troops in 1965. Some American analysts hoped that the diplomatic recall was a precursor to a North Vietnamese peace offer.
With the death of Thanh, General Vo Nguyen Giap became the unrivalled strategist for the North Vietnamese war effort. Giap ironically embraced Thanh’s war strategy after having opposed it for two years; whereas Giap had previously advocated using primarily guerrilla tactics against the U.S. and South Vietnam, Thanh had advocated general main force action, which had led to the big (and losing) battles in the Ia Drang Valley in 1965. Now Giap decided that the time was ripe for a major conventional offensive. Giap and the North Vietnamese leadership came to this conclusion out of an odd combination of hard-headed realism and head-in-the-clouds Marxist ideology. They thought their military position was weakening, and would continue to deteriorate without some dramatic act. This calculation was largely correct. They also thought that the South Vietnamese government and the U.S. presence were so unpopular in the South that a broad-based attack would spark a spontaneous uprising of the South Vietnamese population, which would enable the North to sweep to a quick, decisive victory. This calculation was wholly fantastic, and would prove to be the undoing of the Tet offensive.
By September the signs of a new North Vietnamese initiative were starting to emerge. North Vietnam announced substantial new military aid agreements with both China and the Soviet Union. (There were nearly 4,000 Soviet "advisers" in North Vietnam at this time, some of them manning surface-to-air missile batteries.) U.S. and South Vietnamese forces soon began noticing that Viet Cong and North Vietnamese forces were equipped with new AK-47 assault rifles and B-40 rocket launchers. The North also increased the tempo of its propaganda activities. One of the obvious difficulties with trying to carry off a surprise attack of this kind is that it is necessary to communicate the plan and its objectives to all of the Viet Cong cadres and "sleepers" in place in South Vietnam. It is obviously impossible in such a war to communicate with all the cadres by telephone or telegram. Yet the odd idiom of Communist propaganda and bombast is ideal for communicating a general outline of a battle plan concealed amidst a jumble of slogans and boilerplate jargon about smashing American imperialism and its South Vietnamese puppets. Ideological cadres understand the significance of such messages and could "decode" their meaning, while U.S. eavesdroppers were mostly just bored. In September Radio Hanoi broadcast General Giap’s battle message, "The Big Victory, The Great Task," which was in fact an outline for the Tet offensive. Americans and South Vietnamese listened as Giap’s message said that the time had come for a major offensive against U.S. forces, but also including an attack on South Vietnam’s cities. "U.S. generals," Giap said, "are subjective and haughty, and have always been caught by surprise and defeated." Key to Giap’s strategy was the view that the U.S. would not decide to send major reinforcements beyond to already announced troop ceiling of 525,000. "The longer the enemy fights," Giap observed, "the greater the difficulties he encounters."
Knowing that Americans would hear Giap’s war message, North Vietnam masked its seriousness with the first of several effective diversions. Days before the broadcast, North Vietnam struck hard at the U.S. base at Con Thien near the DMZ (using, among other new Soviet-supplied weapons, large gauge long range artillery for the first time). The North Vietnamese judged—correctly, as it turned out—that the U.S. would make a connection between the broadcast of the battle message and the Con Thien siege. At the same time, North Vietnamese and Viet Cong forces stepped up the tempo of skirmishes along the Laos-Cambodia-South Vietnam border, successfully drawing U.S. forces away from the cities.
Throughout the Fall the signs of a major attack continued to accumulate. In October the number of trucks observed heading south on the Ho Chi Minh trail jumped from the previous monthly average of 480 to 1,116. North Vietnam also announced in October that it would observe a seven-day truce from January 27 to February 3, 1968, in honor of the Tet holiday. Such truces had always been honored in the past—the North Vietnamese usually used the truce period (which typically meant a short halt in U.S. bombing as well) to resupply, and South Vietnam used truces to allow many of its troops to take a short leave. With the North’s announcement of the Tet truce, the South Vietnamese army made plans to allow half of its troops to go on leave during Tet.
In November the number of southbound trucks spotted on the Ho Chi Minh trail jumped again, from 1,116 counted in October to 3,823—an eightfold increase over the previous year’s monthly average of 480. A series of documents were captured that outlined the battle plan in general terms (including the notebook released to the media on January 5 mentioned above). North Vietnam began conducting a swift and brutal purge of officials who urged negotiations with the U.S. rather than a military offensive. Over 200 officials, some of them very senior in the Communist party and the government, were arrested and given long prison sentences. Some were executed. There would be no doves in Hanoi. Near the end of November a CIA analyst named Joseph Hovey circulated a memorandum to U.S. leaders including President Johnson that predicted a major North Vietnamese offensive against South Vietnamese cities in the coming months. Hovey’s analysis was dismissed as unrealistic.
In December the signs intensified. The number of trucks seen on the Ho Chi Minh trail nearly doubled again, from 3,823 spotted in November to 6,315. On December 20 Gen. Westmoreland cabled a warning to Washington, explaining that the signs suggested that North Vietnam had decided "to undertake an intensified country-wide effort, perhaps a maximum effort, over a relatively short period." President Johnson, then in the midst of a state visit to Australia, warned that the desperate North Vietnamese might engage in "kamikaze attacks." But he made this warning privately to the Australian cabinet; no public acknowledgement was ever made in the U.S. that trouble might be brewing. Following North Vietnam’s January 1 offer to negotiate in exchange for a bombing halt, Westmoreland judged that the prospective offensive was an attempt "to gain an exploitable victory before talks so that he might negotiate from a position of strength." This is exactly what the North Vietnamese had done to the French in 1954 at Dien Bien Phu.
With the memory of Dien Bien Phu prominently in mind, Westmoreland and U.S. leaders cast their eyes up to the large U.S. base at Khe Sanh, located in a northern province of South Vietnam not far from the De-Militarized Zone (DMZ). Four divisions of North Vietnamese regular army troops—over 40,000 troops—were massing near Khe Sanh, where 5,000 U.S. and South Vietnamese troops were stationed, in what looked like a repeat of the Dien Bien Phu strategy. Westmoreland and U.S. intelligence thought that all this Viet Cong talk of an uprising in the cities was a diversion away from Khe Sanh, where the main attack was expected to fall. They had it exactly backward: Khe Sanh was the deception, intended to draw U.S. attention and resources away from the cities, and the U.S. largely fell for it. The U.S. calculation actually made good sense. U.S. intelligence knew that there was little prospect for a spontaneous uprising of the South Vietnamese populace, and couldn’t believe that the North Vietnamese and Viet Cong believed it. (It turned out that many VC cadres on the ground in the South didn’t believe it either, but never told their higher ups. Several VC officers captured during Tet told interrogators that they never expected an uprising in their assigned area, but carried out their attack in hopes that it would stir an uprising in other cities.) In an ironic way the blinders of Communist class struggle ideology helped serve the purpose of deception.
So even as more intelligence accumulated in January that an attack on South Vietnamese cities was a serious prospect, U.S. war planners continued to downplay the threat and misjudge the timing. On January 9 U.S. intelligence received a captured document that described a reorganization of the command structure of Viet Cong forces. "At the present time," U.S. analysts wrote, "no explanation is available as to the reason for this reorganization." Caches of weapons and propaganda leaflets calling for an uprising were found near Saigon throughout January. Well-equipped VC sapper teams were caught infiltrating areas near U.S. bases. The National Security Agency, which collects and analyzes "signals intelligence" (SIGINT), reported that radio intercepts indicated preparations for attacks on cities in the central coast region of South Vietnam, and increased enemy activity near Saigon. But based on the predominance of radio traffic near the borders and the DMZ, the NSA still thought, along with Westmoreland, the main blow would come at Khe Sanh. Only General Fred Weyand thought that the action elsewhere might be significant. On January 10, Weyand, the commander for the southern region of South Vietnam including Saigon and the Mekong River delta, canceled plans to move troops in his sector toward the Cambodian border, and ordered 15 battalions to be redeployed near Saigon, a fortuitous move that greatly aided the defense of Saigon during Tet. But neither Weyand nor anyone else in high command thought that the attack would come during the Tet holidays, and over half of U.S. combat forces were detailed for the northern provinces, away from the cities.
As more signs and enemy troop movements were reaching a crescendo in mid-January, a new distraction occurred several thousand miles away. On January 10, the U.S. Foreign Broadcast Information Service published the transcript of a North Korean radio broadcast in which the North Koreans threatened to take action against U.S. Navy surveillance ships operating in international waters off North Korea, which patrolled there to keep tabs on the Soviet fleet operating out of Vladivostok. The threat was ignored. Up until June 1967, lightly-armed U.S. spy ships enjoyed an escort of two destroyers. But the destroyers had been reassigned, and no notice of the North Korean threat was sent to the Navy. North Korean harassment of U.S. spy ships was routine, so when North Korean PT boats began circling the U.S.S. Pueblo on January 23—as they had done several times in the previous few days—the Pueblo’s captain Lloyd Bucher saw no reason for special concern. But this day the North Koreans boarded the slow-moving Pueblo, whose top speed was 13 knots. The crew belatedly tried to smash much of its sensitive intelligence equipment and throw code and cipher books overboard, but the North Koreans still captured an estimated 600 pounds of classified information—an intelligence bonanza for the Soviets, who were en route to North Korea within hours of the Pueblo’s capture. Most valuable of all, the Soviets received an only slightly damaged KW7 cipher machine off the Pueblo, which was the standard code equipment of the U.S. Navy. (The U.S. Navy took no chances, changing codes and cipher keys fleetwide within hours. U.S. intelligence felt the KW7 machine would be of little use without the cipher keys and code books. Alas, the Soviet Union was already receiving U.S. naval code keys from the Walker family spy ring, which would not be broken until 1985. The Soviets were able to read U.S. Navy coded transmissions like an open book for much of that time.) Although it took over two hours to tow the Pueblo into North Korea’s Wonsan harbor, the U.S. was powerless to come to the Pueblo’s aid. The four warplanes on alert at U.S. bases in South Korea were outfitted for nuclear weapons; it would have taken three hours to refit them for a close support mission. All other U.S. planes in the region were out of range. The Pueblo was the first U.S. Navy ship captured since 1807, during the Napoleonic wars.
The White House went into full crisis mode, assembling many of the same advisers and conveying much of the mood of the Cuban missile crisis six years before. Secretary of State Dean Rusk candidly called the Pueblo’s seizure "an act of war." Congress was in an uproar, with the notable exception of Senate Foreign Relations Committee chairman William Fulbright, who said we might find out what really happened "in two or three years. We’re just now finding out what took place in the Gulf of Tonkin."3 A Navy carrier battle group was dispatched to take up position off North Korea, and an assassination attempt against South Korea’s president a few days later kindled additional fears that war might erupt again on the Korean peninsula. President Johnson agreed to a limited call up of U.S. reserves—a move he had resisted for Vietnam—and a buildup of U.S. forces in the Far East, but decided to pursue a diplomatic solution to the Pueblo crisis. (The 83 crewmen were finally released 11 months later, after suffering torture and humiliation, and during which time North Korea missed few opportunities to taunt the U.S. Bucher was later tried in a naval court of inquiry for having given up the Pueblo without a fight.)