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84. Editorial Note

A comprehensive analysis of the Tet offensive by the intelligence community began in February 1968. Director of Central Intelligence Richard Helms met with the President's Foreign Intelligence Advisory Board (PFIAB) on February 16. Helms noted that pre-Tet intelligence was deficient in terms of predicting “the precise time of the urban attacks, their widespread scale, and their intensity” because of the lack of penetration of the Viet Cong, inadequate dissemination and analysis procedures, and poor performance by the South Vietnamese intelligence service. (Central Intelligence Agency, DDO/IMS Files, Job 79–207A, US–8 President Files, US–8 January 1968 to December 1968) In a February 23 letter to Helms, Maxwell D. Taylor, PFIAB Chairman, requested that he cooperate in a study to determine “to what extent, if any, our intelligence services and those of our allies were at fault in failing to alert our military and political leaders of the impending large-scale attack on the cities and towns of South Vietnam.” Taylor posed two questions: “Did our intelligence collection agencies obtain all or most of the pertinent intelligence which was available in the circumstances?” and “Was the evaluation of the available intelligence sound and did that evaluation reach the decision-makers in time to assist them in taking appropriate action?” He requested a response by April 1. (Ibid., Executive Registry Subject Files, Job 80–R01580R, PFIAB Subject File, 285. Tet Offensive)

In a letter to Taylor on April 1, Helms noted that the U.S. intelligence agencies in Washington, the Joint Staff, the staff of the Commander in Chief, Pacific, and the agencies in Saigon had begun the study. The report had not been completed, however, due to “the complexity of the task, the vast amount of material to examine, the necessity to interview commanders and intelligence officers in the field, and our desire to minimize the additional load placed on these officers.” Helms did transmit to Taylor an interim report entitled “Intelligence Warning of the Tet Offensive in South Vietnam.” Principal among the findings of the interim report was the fact that advance warnings of some of the attacks had been given to senior officials and “as a result, a series of actions were taken in Vietnam which reduced the impact of the enemy offensive.” However, other factors to a great extent mitigated this achievement. Numerous reports described attacks on other dates in other areas. In addition, there was a lack of awareness of the full scope of the offensive since the enemy, in emphasizing security even over coordination, had “compartmented” his plans for attack. Despite the abundance of intercepted messages and reports, the exact timing and the scale of the offensive had not been determined beforehand. Not surprisingly, [Page 241]most of those who knew about the coming enemy attack “did not visualize the enemy as capable of accomplishing his stated goals as they appeared in propaganda and in captured documents.” Finally, the “urgency” of the attacks felt by those on the ground in Vietnam was not immediately grasped in Washington. (Ibid.)

The final report to PFIAB evaluating the quality of U.S. intelligence before and during Tet, completed on June 7, was received by President Johnson on June 11. The conclusions of the report were:

  • “a. that the intelligence at hand contributed to the decision on January 25 to cancel the Tet truce in I Corps and to General Westmoreland's action on January 30 putting U.S. commanders on full alert throughout all of South Vietnam just prior to the main attacks;
  • “b. that intelligence contributed substantially to the result that the attacks on the cities were beaten off and that no permanent lodgements were achieved;
  • “c. that the intelligence bearing on the Tet offensive proved adequate in that it alerted U.S. commanders in time to permit them to carry out their missions successfully and, therefore, there are no grounds to support the charge of a major intelligence failure;
  • “d. that the finished intelligence assessments and reporting at the Washington level did not convey the same sense of urgency of the developing military situation as those reaching decision-makers in Saigon and often arrived too late to satisfy the demands of senior officials for prompt information.”

PFIAB recommended that the “normal intelligence process” be examined for ways in which its defects could be overcome. (Memorandum from Taylor to the President, June 7; Johnson Library, National Security File, Intelligence File, PFIAB, Vol. 2)