Foreign Relations of the United States, 1964–1968, Volume IV, Vietnam, 1966

219. Intelligence Memorandum Prepared in the Central Intelligence Agency¹

SC No. 09624/66

Washington, August 26, 1966.

THE VIETNAMESE COMMUNISTSʼ WILL TO PERSIST

Principal Findings

1. So long as the U.S. air offensive remains at present levels, it is unlikely to diminish North Vietnamʼs continued ability to provide materiel support to the war in the South. North Vietnam is taking punishment on its own territory, but at a price it can afford and one it probably considers acceptable in light of the political objectives it hopes to achieve.

2. The Viet Cong have borne the brunt of Communist personnel losses in South Vietnam and have also had to compensate for losses of North Vietnamese personnel. We believe that the Viet Cong capability to recruit and train manpower is adequate to cover losses estimated for 1966 but will probably be inadequate to compensate for casualties and losses in 1967. During 1967 the North Vietnamese will have to assume most of the burden of expanding force levels, and an increasing role in replacing losses. These manpower requirements can almost certainly be met from North Vietnamese resources, but they will impose additional strains on North Vietnamʼs limited supply of skilled personnel and leadership cadre.

3. The Communistsʼ present strategy is costly in both human and economic terms and is taxing Communist resources in some areas, particularly within South Vietnam itself. Allied actions are complicating Communist efforts and raising the costs of their execution. However, neither internal resource shortages nor allied actions within present political parameters are likely to render the Vietnamese Communists physically incapable of persisting in their present strategy.

4. In absolute numerical terms the Communists cannot hope to match present and projected Allied force commitments. However, if present estimates of Allied and Communist force projections are accurate, by mid-1967 the Communists will have a slight advantage in maneuver battalions—i.e., tactical combat troops available for commitment to offensive ground operations.

5. Nevertheless, if they are objective, the Communists must acknowledge that during the past year their insurgent campaign has lost momentum in both the military and political fields. Although they may not be losing the war at the present time, they are certainly not winning it. The Communists are far from being defeated; but they are faced with problems greater than any they have had to contend with before in this struggle. Furthermore, Communist forces have at least temporarily lost the aura of invincibility which was one of their most potent political assets.

6. Morale within Communist military forces and the political apparatus in South Vietnam has declined since mid-1965 but not to a point presently sufficient to force any major revision in basic Communist strategy.

7. The Communists must be disappointed in comparing the present situation with that which existed in the spring of 1965. At least indirectly, they have acknowledged that the infusion of U.S. and Allied combat forces has created new problems which must be overcome before victory can be won. Yet Communist realism is presently tinged more with defiance than pessimism; the Communists may be disappointed, but they do not yet seem to be discouraged.

8. Consideration of world popular opposition to U.S. policy would certainly enter into any eventual Vietnamese Communist decision on whether to revise present strategy but would most certainly not be a decisive factor.

9. The Vietnamese Communists pay close attention to evidence of opposition to current U.S. policy arising within the United States itself. The outcome of their previous struggle with the French almost certainly predisposes them to draw invalid parallels to French domestic opposition in the Indochina war and to look for signs of American domestic political pressures capable of forcing policy changes on Washington.

10. The timing of any Vietnamese Communist decision on altering basic strategy—and the nature of such a decision—will be greatly affected by a variety of considerations, including those outlined in this paper. We estimate that none of the pressures upon the Communists which we can now identify is severe enough to force a major change in Communist strategy over the next eight to nine months. The Communists would be even less inclined to alter their strategy if they should find political and military developments during this period running in their favor—for example, serious political deterioration in South Vietnam, a series of major Viet Cong military successes, or what they construe as a significant rise of anti-war sentiment in the United States. If on the other hand pressures on them are maintained and the course of events gives them no grounds for encouragement, by late spring of 1967 they will probably feel compelled to take stock and consider a change in their basic strategy.

1. Source: Johnson Library, National Security File, Country File, Vietnam, Southeast Asia, Special Intelligence Material, vol. X. Top Secret; [codeword not declassified]. The source text, pages 19–21 of the memorandum, is attached to an August 29 memorandum from R.J. Smith, CIAʼs Deputy Director for Intelligence, to Rostow, under cover of which Smith sent Rostow a copy of the full study; the full study has not been found in Johnson Library files.

   Helms sent the President pages 1–21 of the study, consisting of the “Summary Discussion” and “Principal Findings,” under cover of an August 29 memorandum, in which he noted that McNamara had asked CIA to undertake the study several weeks earlier. Helms noted that he had sent copies of the full study, which included several hundred pages of basic material backing up the “Principal Findings,” to McNamara, Rusk, and Wheeler. (Central Intelligence Agency, DCI (Helms) Files, Job 80–B01285A, Chrono, Jul-Dec 1966) Helms also briefed Senators Mansfield, Russell, and Fulbright on the study on September 19 and summarized the discussion that followed in a memorandum to Rostow, September 20. (Johnson Library, National Security File, Agency File, CIA) Rostow provided the President with his summary of this study in Document 239.