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

296. Memorandum From the Director of the Policy Planning Council (Rostow) to the Secretary of State¹

Washington, August 5, 1964.

SUBJECT

• Speculation on the Background and Possible Implications of the Tonkin Gulf Incidents

1. The Setting. The North Viet Nam PT-boat attacks occurred against a background marked, in recent weeks, by divergent tendencies as seen from Hanoi:

a. Their military and political prospects in South Viet Nam have substantially improved, and this fact was appreciated and reflected, for example, in General Giap’s speech of July 26.

b. On the other hand, the U.S. commitment to the defense of Southeast Asia and support of peripheral offensive actions increased both in Laos and in Viet Nam. The covert moves against North Viet Nam and the discussion of the possibility of more direct action against North Viet Nam have been, evidently, taken seriously despite the evident desire of President Johnson to limit the terrain of conflict. They may have reckoned that this danger would rise in the months ahead, notably after our election.

It is out of this mixed setting of simultaneously enlarged hopes and fears, with perhaps a sense that time might not be their friend, that they took a course extremely difficult to explain by attacking directly units of the Seventh Fleet.

2. Alternative Theories. The following four major hypotheses might explain the action.

a. The least likely, that the attacks on the Seventh Fleet were an effort to seek a response which could be used as a provocation for a previously planned massive military assault on Laos and South Viet Nam either by the overt use of ground forces across frontiers or by forces previously secreted in those areas.

b. More likely, Hanoi may have concluded, on the basis of its assessment of SVN politics, that a U.S. failure to react sharply to these attacks might have persuaded the Khanh government that further reliance on the U.S. was unprofitable and that Saigon should seek the best terms it could find with Hanoi. The incident may have been linked in its timing to such a planned or hoped for cave-in by the GVN.

c. The attacks could be a device for so raising the international noise level and anxiety about war in Southeast Asia as to force the U.S. into a conference in which the issue of the violation of the 1954 and 1962 Accords would be obscured; that is, they could have regarded the move as a device to place us in a position of negotiating under conditions where it would be extremely difficult for us to continue to increase direct pressure on the North, while they continued their military and political campaign in the South, hoping, as in 1954, for a Dienbienphu during the conference. U.S. acceptance of a conference on such terms would be assessed in Hanoi as a damaging, if not mortal, blow to GVN morale.

d. The attacks may have been intended as a limited reaction to covert intrusions into the North, and the raised level of our support in SVN and Laos, probably designed to make us back off or to deter us from conducting further operations of this type or from continuing to expand our commitment in the area.

3. Comment on the Hypotheses. We know of no evidence to justify the view that a massive ground force attack by the Communists in Southeast Asia is planned. However, a heightening of all forms of intelligence collection on Communist troop dispositions and movements in Southeast Asia does appear justified. The hope that the U.S. might respond so passively as to trigger a cave-in or coup inside Saigon is a more tenable hypothesis; although the political evidence available from South Viet Nam does not make a connection clear. What is clear, however, is that a failure to react vigorously by the U.S. might, in fact, have had the result of inducing Khanh to throw in his hand. One likely strand in their action was a felt need to make a show of force in the face of our increasing involvement in the area. So far as a conference is concerned, what is clear is that a direct U.S.-Hanoi confrontation may prove a more effective way of forcing us to the conference table, in their view, than a focusing of attention on the state of the 1954 and 1962 Accords, taken by themselves.

In short, we cannot give a straight, confident answer to the question: Why did they do it? The most likely elements appear a desire to make a show of force against us; a desire to force us to the conference table on unfavorable terms; and the hope that we would so behave as to weaken the political base in Saigon.

4. The Next Stage. On the whole, it is likely that they did not count on a response as substantial as that now under way. From their point of view, the U.S. strike will appear a rather massive countermove, however limited it may be judged by us. It will create a new situation. Specifically, we would agree in general with the memorandum of August 4 to you from Tom Hughes,² suggesting that they would feel impelled to increase their actions in South Viet Nam and, perhaps, in Laos; that they would seek to bring us to the conference table on unfavorable terms; and that the Chinese Communists might make some move of limited support in air defense, at least.

As a contingency matter, however, we should be prepared for the possibility that Hanoi will feel itself so cornered or humiliated as to feel impelled to engage their ground forces, which constitute their major unused asset, more overtly and substantially in Laos or, even, in South Viet Nam than the Hughes memorandum suggests. This might be more likely if Hanoi interpreted the military deployments we will now be making in the Pacific for deterrent purposes as the prelude to massive attack. Lacking lucid communication from us, they may undertake what they would regard as preemptive action on the ground.

5. Policy Consequences. The Tonkin Gulf incidents, taken as a whole, are likely to have a momentum of their own which we should seek to direct for our own purposes. Specifically, they will tend to shift the vision of the problem out of the context of a struggle for control over Southeast Asia by local Communists, with the U.S. as marginal defenders of the area, to one of direct U.S. confrontation with the Asian Communists. As we suggested to George Ball and Harlan Cleveland last night,³ this requires of us, in our Security Council presentation, to ensure that the Tonkin Gulf incidents do not become the exclusive focus for discussion but are kept in the larger perspective of purposeful Communist violation of the 1954 and 1962 Accords. It also would make advisable that we strictly discipline our public reporting on the air strike against North Viet Nam to portray the action as an essentially limited retaliatory move, minimizing the details of military reporting, ancillary damage, etc.

The fundamental issue raised by these incidents, however, is the following: (a) if a limited Communist response permits, should we seek to treat these incidents as closed by our action, while we carry forward substantially our present policy on Southeast Asia; or (b) should we take the occasion of these incidents and the perhaps transient unity they bring about in U.S. public opinion and the Congress, to move on to force Hanoi to cease its aggression and to return, essentially, to compliance with the 1954 and 1962 Accords.

I believe it is to this fundamental choice that you and the President may wish to address yourselves as the hour-by-hour events of the occasion unfold. Public opinion at home and abroad will require prompt decision and continuing leadership if the Tonkin Gulf incidents are not to result in confusing debate which could gravely weaken our position in Southeast Asia and elsewhere. Although the Communist response to our retaliatory strike may determine the choice for us, we should seek to guide the forces set in motion by the Communist attacks on our fleet, to the maximum extent possible.

In any case, as we go forward from these incidents and try, by whatever route the President chooses, to move towards a settlement which would restore the 1954 and 1962 Accords, we shall have to shift focus quite rapidly from the Tonkin Gulf incidents themselves to the basic problem of indirect Communist aggression in Laos and South Viet Nam

1. Source: Department of State, S/P Files: Lot 70 D 199, Vietnam. Secret. Initialed by Rostow and sent to Rusk through S/S. The source text bears the handwritten notation “Secretary Saw.” Also published in Declassified Documents, 1979, 92C.
2. Published ibid., 92A.
3. The only record of a meeting at which Rusk, Ball, Rostow, and Cleveland were present on August 4 is an entry in the Secretary’s appointment book for 5:30 p.m. (Johnson Library)