399. Memorandum From the President’s Special Assistant (Rostow) to President Johnson1

Mr. President:

Herewith Dick Helms’ memo to you on a new National Intelligence Estimate entitled “Capabilities of the Vietnamese Communists for Fighting in South Vietnam.”2 I have marked its main conclusions, summarized on the last two pages.

It comes to this:

  • —manpower is the major problem confronting the Communists;
  • —there has been a substantial reduction in guerrillas since an estimated peak in early 1966;
  • —there has been a slight reduction in main force units in the past year, but this has been possible only by using more North Vietnamese replacements in Viet Cong units;
  • —there is a “fairly good chance” that the Communist military strength and political infrastructure will continue to decline;
  • —Communist strategy is to sustain a protracted war of attrition and to persuade the United States that it must pull out or settle on Hanoi’s terms. Their judgment is that the “Communists still retain adequate capabilities to support this strategy for at least another year.”

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The memo to you and the introductory note reflect a considerable debate in the intelligence community. The debate centers on the fact that they now know more from captured documents than they did about guerrillas, village defense forces, etc. What they know indicates that guerrilla strength was probably underestimated last year, but has declined substantially since.

I had urged that they do a retroactive estimate showing that decline; but they say they cannot do it, and confine themselves to the simple statement that the guerrillas “have suffered a substantial reduction.”

The estimate does not deal with an important fact as estimated by Westmoreland and the JCS: namely, that there has been a very substantial decline in the past year in enemy main force battalions rated as “combat effective.” (Buzz Wheeler told the group the other day, and confirmed to me on the telephone this morning that in October 1965 the enemy had 123 maneuver battalions, all rated combat effective. In October 1967 the enemy had 162 maneuver battalions, of which only 87 were rated combat effective.)

In general, this is a conservative estimate; but it is not a bad thing to build our plans on conservative estimates.

The one danger, of which Dick Helms is aware, is that the underestimate of guerrillas in 1966 be taken out of context and distorted, if leaked. They have tried hard to avoid that possibility.

I told Dick that the one sentence I would challenge is the marked sentence on page 1. I agree that the guerrilla figure was underestimated in 1966; but we have suffered in other areas from overestimation as well as underestimation in dealing with Communist capabilities. But that is not important.

  1. Source: Johnson Library, National Security File, Country File, Vietnam, 3E(1)a, Future Military Operations in VN. Top Secret. The notation “ps” on the memorandum indicates that the President saw it. According to a November 20 memorandum from Bundy to the President, Rostow recommended that a briefing on the estimate “be held up until Westmoreland gives an over-all picture of the military side of the war in all its aspects.” Rostow argued that the fact that guerrilla strength was underestimated in the past and that some groups were removed from the aggregate total would cause “cynical reactions” unless a wider picture of the war was presented. (National Archives and Records Administration, RG 59, Bundy Files: Lot 85 D 240, Top Secret WPB Chron, Nov/Dec 1967)
  2. Document 397.