From 1968 until his death in 2005, General William C. Westmoreland maintained that the Tet Offensive had been a major Communist defeat. He based his argument on the enemy’s purported high personnel losses during the offensive. According to Westmoreland, the U.S. won at Tet because it killed tens of thousands of Vietcong and North Vietnamese. If the war had been strictly a war of attrition divorced from any political context, and the number of dead on each side determined the victor from the vanquished, Westmoreland’s argument would have held some merit.
But the Vietnam War was if anything complex. It was far more than a contest over who racked up the highest body count. It contained elements of a political and economic struggle between a privileged urban minority and an oppressed rural majority. It was also a sectarian conflict between Buddhists on one hand and Catholics on the other. The war also pitted Communist Internationalists against Capitalist Internationalists and Communist Nationalists against Liberal-Democratic Nationalists. Interjected into the struggles amongst the Vietnamese was the larger great power rivalry between the United States, the Soviet Union and Communist China. And yet, even if the war had been exclusively a war of attrition, Westmoreland’s claims of victory at Tet would have still been untrue. There were two reasons for this. First, Westmoreland miscalculated the number of Communist military dead. And second, the Communists rapidly replaced their Tet losses.
A week into the offensive, Military Assistance Command – Vietnam (MACV) estimated that 24,199 Vietcong and North Vietnamese had been killed by the Allies and another 5,007 had been captured. A total of 6,000 to 7,000 of the dead were believed to have been North Vietnamese regulars; the remainder of Communist dead were as Chairman of the Joint Chiefs of Staff General Earle Wheeler noted, “…a mixed variety of South Vietnamese enemy.” The National Intelligence Board (which consisted of key members of the U.S. intelligence community) calculated that an additional 1.5 soldiers suffered wounds for every Communist killed in action. If those numbers held true during Tet, MACV’s estimate of enemy losses at the end of the first week of the offensive meant the Americans and South Vietnamese killed, wounded, and captured a total of 65,504 Vietcong and North Vietnamese soldiers.
Early in the offensive, U.S. intelligence had determined that upwards of 45,000 Communist soldiers participated in the first Tet attacks. If we accept Westmoreland’s enemy loss rate for the first week of the offensive, then the Americans and South Vietnamese not only killed, wounded, or captured the entire initial Communist assault force, but they had inflicted an additional 20,504 casualties on the North Vietnamese and Vietcong. Of course, this was highly improbable; there exists no hard evidence that the Allies inflicted such grievous casualties on Communist military forces in the first days of the offensive.
There are three possible explanations for Westmoreland’s faulty numbers: 1) Westmoreland overestimated the number of enemy casualties and POWs, 2) the Communists committed a far larger military force to the initial attacks than MACV believed, or, 3) the Allies killed a sizable number of innocent civilians or Vietcong support personnel and recorded them as enemy combatants. The Central Intelligence Agency believed in the last explanation. Its analysts wrote, “[MACV’s] …reported casualties are greatly inflated by inclusion of low level recruits and impressed civilians.” The CIA’s conclusion was consistent with what Defense Secretary Robert S. McNamara learned back in mid-1965 – U.S. military operations killed a large number of South Vietnamese civilians who served as temporary Vietcong support personnel. McNamara told President Johnson on July 2, 1965, “…Of the numbers that are killed by Air Force actions, and a great bulk of these people are killed that way, I would think that 75 percent are probably not from what we call the…guerrilla force.”
At the end of February 1968, MACV and the Joint Chiefs of Staff asserted that the Allies had killed or captured 48,000 Communist soldiers since the commencement of the Tet Offensive a month earlier. When MACV released the 48,000 KIA/POW figure, the CIA again questioned the veracity of those numbers. In a meeting with President Johnson on February 28, the Director of Central Intelligence, Richard Helms, remarked, “I worry about those figures on casualties and enemy strength being used. I am not sure how accurate they are.”
Nevertheless, MACV continued to make unsubstantiated claims on enemy casualties. In April 1968, Westmoreland asserted that the U.S. and South Vietnamese had killed 45,000 enemy soldiers over the course of the Tet Offensive. Another 15,000 Communist troops had been killed in the vicinity of Khe Sanh, primarily by U.S. airstrikes. Again, if we accept the National Intelligence Board’s calculation that the enemy suffered 1.5 wounded for each man killed in action, then the total number of Vietcong and North Vietnamese killed and wounded during Tet came close to 150,000 or 62 percent of the entire Communist military force supposedly in existence in early 1968 in South Vietnam, which had been pegged by MACV at 241,400 main forces and guerrillas. Tet indeed would have been a major Communist defeat if Westmoreland’s casualty figures had been correct. The Vietcong and southern-based North Vietnamese Army would have been seriously impaired in their ability to continue the war. But Westmoreland, as was so often the case during his years in Saigon, got it wrong.
It was readily apparent to observers on the ground in South Vietnam that the Vietcong and North Vietnamese had not suffered the casualty rates claimed by MACV because there existed such an obvious disparity between what MACV stated as fact and what was actually happening on the battlefield. Namely, the Vietcong and North Vietnamese continued to fight all across South Vietnam. Additionally, if the southern Communist military structure had been decimated at Tet, it would not have been able to launch mini-Tet in May or continue the war at a high intensity throughout the remainder of 1968. Undoubtedly, Westmoreland included in his casualty totals large numbers of the Vietcong’s temporary civilian support personnel killed in U.S. artillery strikes and bombing raids.
MACV’s Intelligence Chief, Lieutenant General Philip Davidson, contended that the Vietcong had suffered so many casualties that, “In truth, the Tet Offensive for all practical purposes destroyed the Vietcong.” The CIA strongly disagreed with Davidson; its analysts believed the Communists rapidly replaced the bulk of their Tet losses through a combination of in-country recruitment and infiltration down the Ho Chi Minh Trail. An estimated 100,000 North Vietnamese passed down the Ho Chi Minh Trail between January 1, 1968, and May 14, 1968. This infiltration, along with an intensive Vietcong recruitment drive in recently acquired territory within South Vietnam, led the CIA to conclude in a March 1, 1968, report, “…It is conceivable that the enemy’s gross strength is not significantly lower now than it was in the latter part of 1967.” In other words, the Tet Offensive did not appreciably diminish Communist military strength in South Vietnam.
After the Tet Offensive ended, the CIA completed a new enemy order of battle (OB) estimate. That OB put the lie to both Westmoreland’s claim of victory at Tet because of the high enemy body count and Davidson’s claim of victory because the U.S. destroyed the Vietcong. The CIA estimated Communist strength in the South, including political operatives, at between 480,000 and 615,000 or “…about twice the previously agreed figures.” These numbers did not include any of the Vietcong’s temporary civilian support personnel – those persons who either volunteered, or were impressed into service, for a specific battle or campaign. Approximately 100,000 to 110,000 of the CIA’s OB total were North Vietnamese regulars. The remainder, or up to 515,000 personnel, consisted of southern-born Vietcong. Thus, rural South Vietnam, rather than North Vietnam, continued to contribute the largest number of men to the Communist force structure in the South. Obviously, the Vietcong were not a spent force.
General Earle Wheeler, Chairman of the Joint Chiefs of Staff, was alarmed by the CIA’s April 1968, OB estimate, not because of its military implications but because of its potential domestic political ramifications. Wheeler believed the new OB, if released to the American public, would undermine the entire American effort in Vietnam. The CIA’s OB would prove that U.S. military operations since early 1965 had failed to make any appreciable headway against the Communist insurgency. Wheeler worried that if the public learned that Communist strength in the South stood at over half a million men and women, even after the losses of the Tet Offensive, the American public would conclude that there was no hope of ever achieving victory in Vietnam. The last vestiges of homefront support for the war would collapse. President Johnson would then face intense political pressure to order a unilateral U.S. withdrawal from South Vietnam. Wheeler sought to forestall that possibility.
Soon after learning of the CIA’s new OB, Wheeler asked Secretary of Defense Clark Clifford to help him suppress its contents. Wheeler wrote Clifford, “There is a much larger issue involved here than intelligence methodology. The acceptance of this inflated strength…is contrary to our national interest. The effect that its inevitable public announcement would have on the American public…is obvious.” Clifford, although by now an advocate of a U.S. pull-out from Vietnam, agreed that the CIA’s new OB would harm the “national interest.” Consequently, the Johnson administration put pressure on the CIA’s Richard Helms to suppress the OB. Helms, recognizing the explosive political nature of the document, decided to withhold it pending a review.
If all of this was not enough to show that the Communists, and particularly the Vietcong, quickly rebounded from Tet, the CIA concluded in a June 6, National Intelligence Estimate, that because of “…new units now in the pipeline [coming down the Ho Chi Minh Trail] and intensified recruiting in the countryside, Communist forces will be capable of undertaking a series of major attacks between now and the fall.” Tet had not crushed the Vietcong; it remained a serious, long-term threat to South Vietnam and the American military position there.
 Foreign Relations of the United States (FRUS), Volume VI, Vietnam, January-August 1968, “Document 60, Notes of Meeting, February 7, 1968,” (Washington, D.C.: GPO, 2002), 143.
 Vietnam Task Force, Office of the Secretary of Defense, The Pentagon Papers, Parts IV.C.6 through IV.C8, “IV.C.6.(a), U.S. Ground Strategy and Force Deployments, 1965-1967, Volume I, (Nimble Books, LLC, 2011), 110.
 National Intelligence Council, Estimative Products on Vietnam, 1948-1975, “Memorandum for DCI, The Outlook in Vietnam, February 26, 1968,” (Washington, D.C.: GPO, 2005), 2.
 Michael Beschloss, Reaching for Glory: Lyndon Johnson’s Secret White House Tapes, 1964-1965, (New York: Touchstone, 2001), 383.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 91, Notes of Meeting, February 28, 1968,” 273.
 Phillip B. Davidson, Vietnam at War: The History, 1946-1975, 1988, Reprint, (New York: Oxford University Press, 1991), 359, 475.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 162, Notes of a Meeting, March 27, 1968,” 482.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 95, Memorandum Prepared in the Central Intelligence Agency, March 1, 1968,” 288.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 202, Memorandum from the Chairman of the Joint Chiefs of Staff (Wheeler) to Secretary of Defense Clifford, April 22, 1968,” 582.
 Ronald H. Spector, After Tet: The Bloodiest Year In Vietnam, (New York: The Free Press, 1993), 76; New York Times, “U.S. Reassesses Composition of Enemy’s Forces,” Neil Sheehan, April 21, 1968; Carver-drafted DIR-cable 75802, 13 February 1968 (S) CIA files, jobno. 80R01720R, O/D/NFAC, Box 3, “GAC Files, (SAVA-NIO),” Folder 9.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 202, Memorandum from the Chairman of the Joint Chiefs of Staff (Wheeler) to Secretary of Defense Clifford, April 22, 1968,” 583.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 220, Memorandum of Conversation, May 3, 1968,” 630.
 FRUS, Volume VI, Vietnam, January-August 1968, “Document 263, Special National Intelligence Estimate, June 6, 1968,” 757.