TET ’68 and the Failure of the American Intelligence Community

Since 1968, historians, and former U.S. military and government officials, have debated whether the American intelligence community failed to predict the Tet Offensive.

General William C. Westmoreland, as well as the Director of Central Intelligence, Richard Helms, claimed then, and later, that the U.S. intelligence system did not fail in the weeks before Tet. According to these two men, both of whom had strong personal and professional reasons for downplaying any intelligence failure, the United States had anticipated the offensive.

Yet, despite the claims of Westmoreland and Helms, the historical record indicates that the U.S. intelligence community did not anticipate the Tet Offensive. Consequently, when the offensive began across South Vietnam on January 30-31, 1968, top U.S. officials, including President Johnson, expressed astonishment at the size and intensity of the Communist military effort.

At the conclusion of the Tet Offensive in February 1968, the CIA carried out an internal review of its intelligence collection and analysis procedures during the weeks prior to the offensive. That review absolved the CIA of operational negligence. The President’s Foreign Advisory Intelligence Board, which included members of the CIA, came to the same conclusion in a June 1968 report, which stated, “…there are no grounds to support the charge of a major intelligence failure.”[1] The board based its conclusion on two pieces of shaky evidence: 1) Westmoreland canceled the Tet truce in I Corps on January 29th, and; 2) Westmoreland ordered U.S. units on full alert across South Vietnam on January 30th.

General Westmoreland canceled the Tet truce in I Corps at 5:00 p.m. on January 29, 1968, only seven hours before the Vietcong began major attacks in that area. Westmoreland ordered this limited truce cancellation because he believed the U.S. Marine base at Khe Sanh faced an imminent, large-scale, North Vietnamese assault. The MACV commander did not cancel the truce in I Corps because he believed the Vietcong and North Vietnamese would conduct attacks on hamlets, towns, and cities within both I Corps and II Corps later that night, nor did he know that Vietcong and North Vietnamese main forces would move on the city of Hue.

Regardless of Westmoreland’s truce cancellation, when the Communists struck in the early morning hours of January 30th at Danang, Ban Me Thuot, Pleiku, Tan Canh (near Dak To), Kontum, Tuy Hoa, Nha Trang, and Qui Nhon, they took the Americans and South Vietnamese based at those locations completely by surprise. New York Times reporter Tom Buckley wrote, “American sources seemed dismayed by the success of the closely coordinated attacks. They apparently caught the Vietnamese army and militia forces, which have primary responsibility for guarding the cities, off guard while they were celebrating [Tet]….”[2]

The attacks on January 30th should have taken place a day later, but because of a Communist communications snafu, Vietcong and North Vietnamese units went ahead and struck across I Corps and II Corps. These premature raids, and not effective U.S. intelligence collection, alerted the Americans to the possibility of additional attacks in the days ahead in other areas of the country.

After the first attacks on January 30th, Westmoreland, now convinced that the Communists would launch further strikes elsewhere, but still not sure where, ordered a countrywide alert at 3:45 a.m., January 30th, about twenty hours before the beginning of a series of major assaults and twenty-three hours before the spectacular attacks in Saigon. The general’s alert was so vague, and came so late, that U.S. and South Vietnamese units were still unprepared for the full fury of the Communist offensive, especially at Hue, Saigon, and the Mekong Delta towns of My Tho and Can Tho. Another U.S. intelligence board, (consisting of members of the CIA, the National Security Agency, the State Department’s Bureau of Intelligence and Research, the Defense Intelligence Agency, and the Joint Chiefs of Staff), which was set up to review U.S. intelligence in the two weeks prior to Tet, wrote in April 1968, “Although warning had thus been provided, the intensity, coordination, and timing of the enemy attack were not fully anticipated…Few US or GVN [Government of South Vietnam] officials believed the enemy would attack during Tet….”[3] The committee continued, “In IV CTZ, [the Mekong Delta] the nature and extent of the enemy’s attacks were almost totally unexpected.”[4]

Westmoreland and General Philip Davidson, MACV’s J-2 (Intelligence) commander, argued in 1968, and for decades afterward, that the re-positioning of U.S. battalions in the weeks before the offensive in and around Saigon provided irrefutable proof that MACV anticipated the Tet Offensive. But the re-positioning of U.S. units toward Saigon reveals that Westmoreland and Davidson expected attacks at Saigon, not across the entire length and breadth of South Vietnam.

Not one top administration official anticipated the offensive. The U.S. ambassador to South Vietnam, the elderly Ellsworth Bunker, who was regularly briefed by the CIA’s Saigon Station Chief and MACV’s J-2, did not see the offensive coming. He wrote President Johnson on January 13, 1968, two and a half weeks before the offensive, that all was well in South Vietnam. The U.S. was making progress; and it should continue with its present strategy and tactics. In other words, America was winning the war. Bunker wrote, “The past year has been one of sustained and unremitting effort and I believe has seen enough achievements to give us every encouragement to continue along the present lines.” The ambassador continued, “He [the enemy] has been thwarted in his attempts at penetration south of the DMZ….” In this report to the president, Bunker made no mention that all hell was about to break loose in South Vietnam.[5]

On January 18th, the Board of National Estimates informed DCI Helms that it could not predict with certainty Communist military actions in 1968. Its members stated, “In present circumstances it is true that any of a multitude of things could happen, at almost any time.”[6] Simply put, America’s top intelligence analysts had no idea what the Communists had planned for 1968.

On January 31, 1968, the day of the Vietcong attacks in Saigon, a CIA analyst stationed in the South Vietnamese capital telegraphed George Carver, the CIA’s top Vietnam expert at CIA Headquarters in Langley, Virginia. Referring to the attacks that received so much television coverage in the United States – including the assault on the U.S. embassy in downtown Saigon, the analyst wrote, “During the last few days, [CIA Saigon] Station has diligently pursued all available sources of intelligence that might have given us warning of these attacks.”[7] The CIA man in Saigon confessed to Carver that the CIA, with its vast network of field operatives across South Vietnam working inside the pacification program, had been caught by surprise at Tet.

Both outgoing Secretary of Defense Robert S. McNamara and incoming Secretary of Defense Clark Clifford, two men privy to the latest intelligence from the NSA, DIA, CIA, State Department, and the various branches of the U.S. military, privately expressed astonishment that the Communists had been able to launch such a major offensive. On the morning of January 31st, as news of the attacks began trickling into the White House and Pentagon, McNamara spoke with Johnson on the phone about the catastrophe then unfolding in South Vietnam. He remarked, “Well, I think it shows two things, Mr. President. First, that they [the enemy] have more power than some credit them with. I don’t think it’s a last grasp effort…After they absorb the losses they will remain a substantial force.”[8] What McNamara was in fact saying was that some U.S. leaders had underestimated the capacity of the Vietcong and North Vietnamese to conduct a general offensive on the scale of Tet. If anything, the Secretary of Defense’s remarks were a sharp criticism of Westmoreland and Bunker, both of whom had recently told the president that the enemy in the South was in decline. Clark Clifford informed President Johnson that members of the Vietnam Task Force, a group with access to the latest intelligence on Vietnam, had been surprised by Tet. He remarked, “Frankly, it came as a shock that the Vietcong-North Vietnamese had the strength of force and skill to mount the Tet Offensive – as they did.”[9]

There were other signs of a massive intelligence failure at Tet. For example, on the morning of January 31st, South Vietnamese leader Nguyen Van Thieu was not in Saigon to direct a defense of the capital. Rather, Thieu was in My Tho visiting his wife’s relatives. Had Thieu been aware of the coming offensive, he would not have been in My Tho, a city nearly taken by the Vietcong. As it turned out, an American helicopter had to evacuate Thieu from the embattled city. Unknown to the Vietcong, they had come close to capturing or killing the leader of South Vietnam.[10]

The fact that half of South Vietnam’s armed forces remained absent for duty at the time of the initial attacks provides further proof that neither the South Vietnamese nor the U.S. knew of the impending offensive. No commander in his right mind would have allowed hundreds of thousands of men to remain on leave had he been aware of a massive countrywide offensive about to take place.[11] Even though President Thieu officially canceled the Tet truce at 9:45 a.m. on January 30th, South Vietnamese military commanders were lackadaisical in calling their men back to duty in time to defend against the offensive. Why? Because the commanders did not believe the offensive would begin that very night. Journalist Don Oberdorfer wrote that on January 30th, there was, “no evidence of a widespread attempt by the Vietnamese government to recall its officers and men to duty.”[12]

In the field, U.S. troops confessed that the offensive took them by surprise. Tobias Wolff, based at My Tho, recalled, “When the assault, the so-called Tet Offensive, first began we didn’t know what was going on.”[13]

The most damning indictment of the U.S. and South Vietnamese intelligence community’s inadequacies prior to Tet came from the Defense Department’s Office of Systems Analysis and from National Security Council staffer William J. Jorden. Systems Analysis wrote, “In short, our setbacks [at Tet] were due to wishful thinking compounded by a massive intelligence collection and/or evaluation failure.”[14] On February 3, 1968, William J. Jorden wrote in a memo to National Security Advisor Walt W. Rostow, “…it is my opinion that the series of well-coordinated NVA/VC attacks in all parts of the country represents a distinct setback to the Government in Saigon and to us…[Tet is a setback because]…among other things, they [the Tet attacks] reflect probably the worst intelligence failure of the war…We didn’t have one single attack thoroughly anticipated, of the many that occurred. Something is rotten in the Vietnamese CIO (the South Vietnamese equivalent of the CIA), the Military Security Service and the National Police. And what about our [CIA] intelligence work in the provinces?”[15]

There is no written evidence that Rostow responded to Jorden’s damning assessment or that he shared the memo’s contents with the president. One possible reason Rostow kept the memo to himself – its contents reflected badly on him. As Johnson’s point man on national security matters, it was Rostow’s job to examine the existing intelligence and predict future threats to U.S. national security – such as a large-scale Communist offensive in South Vietnam. Rostow utterly failed in this respect in late 1967 and early 1968. He did not provide the president any advance warning of the attacks. So, when the attacks did come, the president was surprised too. Details of the attacks at the embassy and other U.S. and GVN facilities in the South Vietnamese capital came into the White House over the wires in the early afternoon of January 30th, (Washington is twelve hours behind Saigon). Rostow conveyed the first reports to the president at 2:35 pm, when he interrupted a meeting attended by Johnson. Rostow told the president and the other assembled officials, “…we are being heavily mortared in Saigon. The Presidential Palace, our BOQ’s, the Embassy and the city itself have been hit.” Upon hearing this stunning news, Johnson, looking around the table, said, “This could be very bad.”[16]

Having let down his president, Rostow attempted to then protect himself and his career. He determined the best way to do that was to downplay the significance of the Tet Offensive.

Only days after the start of the offensive, and weeks before a full accounting of U.S. and South Vietnamese military and territorial losses could be made, Rostow declared Tet a major Communist defeat. In Rostow’s opinion, Tet was a desperate, go-for-broke operation. He argued privately, and publicly, that the Vietcong were on the brink of total collapse and were wildly lashing out at the Allies before falling apart under the weight of high casualties. He even went so far as to contend that Tet provided the U.S. and South Vietnamese with a rare opportunity to exploit the Communists’ newfound weakness. In Rostow’s imaginary world, the Communists were down and the U.S. just needed to knock them out.

Rostow’s version of events completely distorted the realities of Tet, but it achieved one important result – it nullified his glaring professional inadequacies in the months before the offensive. Essentially, Rostow’s interpretation of Tet implied that it did not matter that he, or others in the intelligence community, such as the CIA’s George Carver, did not predict the offensive because Tet was actually a good thing, since in the course of the offensive tens of thousands of Vietcong exposed themselves to U.S. firepower. For Rostow, it was irrelevant that Tet had taken the Allies by surprise. The shock of the offensive’s beginning was negated by its bloody ending.[17]

Rostow’s views, although wrong, influenced Johnson. The president accepted Rostow’s version of events – for the same set of reasons that Rostow adhered to them so fervently. Rostow never wavered in his self-serving assessment of Tet, arguing as late as 1983, in the PBS documentary “Vietnam: A Television History,” that during Tet the U.S. dealt the Communists a significant military defeat.

As for Johnson, Rostow’s skewed interpretation explained away his own sub-par performance as Commander-in-Chief. On February 6th, after reading Rostow’s analysis of Tet and its larger meaning for the U.S. war effort, LBJ remarked to several of his advisers, “I do not share the view that many people have that we took a great defeat [at Tet].”[18]

Several other top U.S. officials, with a lot riding professionally on the outcome in Vietnam, agreed with Rostow’s interpretation of Tet. Ambassador Ellsworth Bunker, General Westmoreland, Joint Chiefs of Staff Chairman Earle Wheeler, and Secretary of State Dean Rusk all claimed Tet as a U.S. victory. In part, Johnson’s advisers adhered to the Rostow line because their pre-Tet statements of progress in South Vietnam would have been shown to be utterly false, and their already frayed professional reputations diminished further, had they acknowledged Tet as a major U.S. defeat. Conversely, those without a history with the war, or who no longer had responsibility for its day-to-day conduct, saw Tet differently, including outgoing Secretary of Defense McNamara, incoming Secretary of Defense Clifford, and former White House adviser McGeorge Bundy.

Director Helms shared responsibility for the intelligence failure at Tet. His job, like Rostow’s, was to forecast Communist actions in South Vietnam. Helms explained away the CIA’s poor performance before Tet by arguing that the Communists had compartmentalized information of their Tet plans and preparations, making it impossible for the CIA to get a clear, overarching picture of the pending offensive. Of course, that was a lame excuse, since every military organization and intelligence service in the world compartmentalized information to protect operational security. It was the job of the Central Intelligence Agency – as its name implies – to synthesize disparate intelligence information into a coherent whole.

In early 1968, Johnson should have fired Rostow, Helms, Westmoreland, and MACV intelligence chief Davidson. But he didn’t because at this point in his flagging presidency Johnson valued blind loyalty over competency. In addition, his fall 1967 “progress tour” boxed him in. If Tet was a Vietcong victory, then Johnson’s “progress tour” would have been revealed for what it was – a complete sham. And as soon as the American people realized that Johnson had deceived them in 1967, and had been deceiving them for years, and that there had never been progress in the war in Vietnam, there would have developed tremendous political pressure on the president to get the U.S. out of South Vietnam as quickly as possible. And so, to keep the U.S. in the war and to prevent an American rout in South Vietnam, Johnson and his team perpetuated the lie of a U.S. victory at Tet. More specifically, the administration proclaimed that the U.S. irrevocably destroyed the Vietcong at Tet. And those false claims served to perpetuate the war for another seven years.


[1] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 84, Editorial Note,” (Washington, D.C.: GPO, 2002), 241.

[2] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 34, Telegram From the Commander of the Military Assistance Command, Vietnam (Westmoreland) to the Commander in Chief, Pacific Forces (Sharp) and the Chairman of the Joint Chiefs of Staff (Wheeler),” (Washington, D.C.: GPO, 2002), 75-77; New York Times, “Viet Cong Attack 7 Cities; Allies Call Off Tet Truce,” Tom Buckley, January 30, 1968.

[3] Central Intelligence Agency, “Intelligence Warning of the Tet Offensive in South Vietnam, https://www.cia.gov/library/readingroom/…/CIA-RDP80R01720R000100080001-8, page 3.

[4] Ibid., page 7.

[5] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 11, Telegram From the Embassy in Vietnam to the Department of State,” (Washington, D.C.: GPO, 2002), 28.

[6] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 19, Memorandum From the Board of National Estimates, Central Intelligence Agency, to Director of Central Intelligence Helms,” (Washington, D.C.: GPO, 2002), 44.

[7] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 40, Memorandum From the Special Assistant for Vietnamese Affairs, Central Intelligence Agency (Carver) to the President’s Special Assistant (Rostow),” (Washington, D.C.: GPO, 2002), 90.

[8] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 37, Editorial Note,” (Washington, D.C.: GPO, 2002), 83.

[9] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 104, Notes of Meeting,” (Washington, D.C.: GPO, 2002), 318.

[10] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 40, Memorandum From the Special Assistant for Vietnamese Affairs, Central Intelligence Agency (Carver) to the President’s Special Assistant (Rostow),” (Washington, D.C.: GPO, 2002), 90.

[11] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 65, Notes of Meeting,” (Washington, D.C.: GPO, 2002), 170.

[12] Don Oberdorfer, Tet: The Turning Point in the Vietnam War, (Baltimore: John Hopkins University Press, 2001), 134.

[13] Tobias Wolff, In Pharaoh’s Army: Memories of the Lost War, (New York: Vintage Books, 1994), 132.

[14] Vietnam Task Force, Office of the Secretary of Defense, The Pentagon Papers, Parts IV.C.6 through IV.C.8, “IV.C.6. (c), U.S. Ground Strategy and Force Deployments, 1965-1967, Volume III,” (Nimble Books LLC, 2011), 27.

[15] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 49, Memorandum From William J. Jorden of the National Security Council Staff to the President’s Special Assistant (Rostow),” (Washington, D.C.: GPO, 2002), 111-112.

[16] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 36, Notes of a Meeting,” (Washington, D.C.: GPO, 2002), 81-82.

[17] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968, “Document 57, Memorandum From the President’s Special Assistant (Rostow) to President Johnson,” (Washington, D.C.: GPO, 2002), 132-134.

[18] Foreign Relations of the United States, 1964-1968, Volume VI, Vietnam, January-August 1968FRUS, Vietnam, Volume VI, “Document 59, Notes of a Meeting,” (Washington, D.C.: GPO, 2002), 139.

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