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

66. Special National Intelligence Estimate¹

SNIE 10–1–66

Washington, February 4, 1966.

POSSIBLE EFFECTS OF PROPOSED US COURSES OF ACTION ON DRV CAPABILITY TO SUPPORT THE INSURGENCY IN SOUTH VIETNAM

The Problem

To estimate how DRV capabilities to support the insurgency in the South would be affected by increasing the scope and intensity of the bombing of North Vietnam, and how long it would take for the impact to be felt in the South.²

Concept of the Courses of Action

The immediate aims of the bombing would be:

1. To destroy those resources already in North Vietnam that contribute most to support of Communist forces in the South;

2. To block external assistance to the DRV;

3. To harass, disrupt, and impede the movement of men and material through the southern DRV into Laos and South Vietnam.

• Course A: The enlarged bombing program would include aerial attacks designed to:

  1. Destroy all known POL facilities in the northern DRV;

  2. Destroy all large military facilities in the northern DRV, except airfields and SAM sites;³

  3. Interdict the land LOCs from China and close DRV ports by various means including mining;

  4. Put and keep electric power facilities out of action;

  5. Carry out armed reconnaissance against land and water LOCs and all identified military facilities. South of the 20th parallel, such reconnaissance would be particularly intensive and carried out day and night.

• Course B: The program above, but without closing DRV ports by mining or otherwise.

Note

This estimate considers only how DRV physical capabilities to support the insurgency in South Vietnam would be affected by certain assumed US bombing attacks on North Vietnam; it does not deal with the possible effect of these attacks on DRV will to continue the war.

Conclusions

A. The combined impact of destroying in-country stockpiles, restricting import capabilities, and attacking the southward LOCs would greatly complicate the DRV war effort. The cumulative drain on material resources and human energy would be severe. The postulated bombing and interdiction campaign would harass, disrupt, and impede the movement of men and material into South Vietnam and impose great overall difficulty on the DRV. However, we believe that, with a determined effort, the DRV could still move substantially greater amounts than in 1965.⁴

B. However, the cumulative effect of the campaign would almost certainly set a limit to the expansion of PAVN and VC mainforce units and activities in South Vietnam. There are too many uncertainties to permit an estimate of just where that limit would be set.

C. If the main ports were not closed, supply of DRV needs from the outside would be greatly simplified, and the problem of moving goods within the DRV would be eased.

[Here follows the 9-page “Discussion” section.]

1. Source: Johnson Library, National Security File, Bundy Files, Vietnam Intelligence. Top Secret; Sensitive; Controlled Dissem. The Central Intelligence Agency and the intelligence organizations of AEC, NSA, and the Departments of State and Defense participated in the preparation of the estimate. The estimate was submitted by the Director of Central Intelligence and concurred in by all the members of the U.S. Intelligence Board, except for the Assistant Director of the FBI, who abstained on the grounds that the subject was outside his jurisdiction.

   Raborn forwarded the estimate to McGeorge Bundy on February 4 together with a 25-page study, dated January 28, on “The Impact of Intensified Air Attacks Against Economic Targets in North Vietnam,” prepared by CIAʼs Office of Research and Reports in response to a request from the Department of State. (Ibid.)

2. In a February 11 memorandum, CIAʼs Office of National Estimates examined the possible short-run effects and the advantages and disadvantages of four different bombing programs against the DRV. (Ibid., Memos to the President—McGeorge Bundy, vol. 20)
3. Constant surveillance of the airfields would be maintained and their destruction undertaken whenever interference with our planned air operations, or any offensive air actions against our military forces in SVN, might be initiated. Any SAM installations threatening to interfere with these operations would be attacked. [Footnote in the source text.]
4. Major General Jack E. Thomas, Assistant Chief of Staff, Intelligence, United States Air Force, believes that this conclusion and the tone of the estimate reflect an under-estimation of the overall impact of the postulated bombing program and closing of the DRV ports. He believes that the cumulative interacting effect of such bombing and port closure on the economy, the military structure and the political and psychological fabric of North Vietnam would degrade the DRV capabilities to support the war in the south to a greater extent than this estimate indicates. By excluding consideration of the North Vietnamese will to continue the war, a very important effect of the postulated bombing and port closing has been eliminated. [Footnote in the source text.]