Foreign Relations of the United States, 1969–1976, Volume XIV, Soviet Union, October 1971–May 1972

201. Memorandum Prepared in the Central Intelligence Agency¹

Washington, May 6, 1972.

SUBJECT

• Soviet, Chinese, Free World Reactions to a US Attempt To Deny Sea Access to North Vietnam

Assumption: The measures that the US might take in an attempt to deny sea-borne imports to North Vietnam could include (a) mining the approaches to ports; (b) bombing of ports to destroy unloading and storage facilities; (c) naval blockade.

1. These measures vary in the sharpness of confrontation they would produce and therefore in the degree of tension and risk which might result. The reactions of the various parties would also vary accordingly.

2. For the Soviets and Chinese, the key questions posed would be the following:

(a) Would Hanoi’s capacity to carry on its war effort be significantly reduced?

(b) Would the US actions be sustained for a considerable period?

(c) Would these portend other US escalatory steps?

(d) Would the countermeasures which might be envisioned carry tolerable risks and be sufficient to uphold the prestige of the Communist powers?

3. It is conceivable, but we judge extremely unlikely, that Moscow and Peking or one of them would respond to the US show of determination by moving to place Hanoi under genuine pressure to reach a compromise settlement. While neither of the Communist great powers has a vital interest in the success of Hanoi’s campaign in South Vietnam, they almost certainly could not agree on this course and each would fear to act unilaterally because of reactions anticipated in other Communist states and parties. Moreover, neither would wish, because of concern for its own standing as a great power, to bear the onus of yielding obviously under US pressure.

4. Thus we believe that Moscow and Peking would respond initially by joint measures to increase supplies to Hanoi via China’s land routes. The capacity of the land routes from China into North Vietnam is adequate to supply Hanoi’s needs over an indefinite period, and we have no doubt that the Soviets and Chinese could agree to cooperate in carrying out supply by these routes if they judged that necessary to sustain Hanoi. Finally, the ability to keep Hanoi going by land supply would give time to consider other measures, and the broader costs and risks which might emerge more clearly as the crisis developed.

USSR Reactions

5. Having decided on these measures to continue support for Hanoi, the Soviets would be primarily concerned to contain the crisis, and to limit the costs to Soviet-American relations generally. Nevertheless, they would consider that their standing as a great power had been directly challenged and would want to act to uphold their prestige.

6. On the political level, Moscow would feel that it had no choice but to react sharply. The machinery of propaganda would be employed with high intensity in order to maximize the pressure of world and domestic US opinion against the US administration. Unless the US desisted and the crisis seemed on the way to resolution within a few days or so, the effect would be to make the May Summit impossible. The Soviets would almost certainly move to cancel it. This step might be delayed somewhat if the US measures were limited to mining, which would pose a less direct challenge to the USSR, but would come in any case if the US persisted.

7. The Soviets would be aware that the damage to the climate of Soviet-American relations generally—to the SALT agreement, to trade prospects, and to détente in Europe—would be severe. But we believe that the Kremlin consensus would come down on the side of paying this price rather than seeming to bow under US pressure. In doing so, there would probably be the intention to return to present lines of policy toward the US as soon as circumstances permitted.

8. There would remain in the question of what specific steps the USSR should take to counter the US moves. While considering these, the Soviets would probably order their ships out of North Vietnamese waters. If the US limited itself to mining North Vietnam’s sea approaches, the Soviets would probably give Hanoi technical assistance in sweeping operations. To bombing attacks on ports they would reply with additional measures to strengthen North Vietnam’s air defenses, but would probably not take overt measures such as sending Soviet aircraft and crews. (Sinking of Soviet ships during such attacks would obviously place the Soviets under great pressure to react more sharply.) A blockade would pose a more direct challenge than bombing or mining. We believe that the Soviets would judge that the risks of an attempt to defy a blockade would be too great, and would avoid doing so. Before the world, they would make a virtue of their restraint and point to their continuing support to Hanoi in other ways.

9. Throughout, the Soviets would be concerned to show an adequate response in support of North Vietnam and in defense of their own prestige. They would be equally concerned to keep the crisis under control and to limit its damage to their wider interests, but would find this increasingly difficult if the crisis was prolonged. They would count heavily on mounting pressures on the US administration at home and abroad to deter further escalation and to force Washington to desist eventually. And they would be prepared at a suitable moment to sponsor a new formula for resumption of negotiations, though still not on terms which Hanoi would judge prejudicial to its interests.

[Omitted here is further discussion on Chinese and world-wide reaction to the blockading of North Vietnamese ports.]

1. Source: National Archives, Nixon Presidential Materials, NSC Files, Box 160, Vietnam Country Files, Vietnam–May 1972. Top Secret. In a May 6 memorandum to Kissinger entitled “Planned Actions,” Lord offered a scenario for and discussed a broad range of reactions that could unfold from the impending decisions on Vietnam, and posited: “No matter what we achieve we nevertheless certainly will suffer some of the losses suggested in the scenario: Summit, SALT, other agreements, at least some cooling with Peking, civilian casualties, etc. We could have other losses: a more serious break with Peking, some Moscow-Peking rapprochement, etc. In short, even if we ‘succeed,’ would there be a net gain?” (Ibid., Box 1330, NSC Unfiled Material, 1972, 5 of 8, Vietnam—Sensitive 1972 USSR Summit)