171. Letter From the Deputy Under Secretary of State for Political Affairs (Johnson) to the Deputy Secretary of Defense (Vance)1

Dear Cy:

The growing number of encounters between U.S. and Soviet ships and aircraft gives us increasing concern over the possibility of a serious incident which in the context of our current relationship with the Soviet Union could have serious political repercussions. As Soviet vessels become involved or involve themselves in our increasing operations off Viet-Nam, the risk of a serious incident inevitably increases. However, our concern is not confined just to the Vietnamese area.

For your own background I am enclosing a copy of a list of recent incidents which I had prepared on the basis of information available to us here.2

We have also studied the Rules of Engagement now in effect and they seem to us to be generally satisfactory. It seems that the Soviet rules are probably similar to our own, but the occasional dangerously close Soviet approaches to our aircraft and ships give us concern that Soviet personnel may exercise considerable latitude in the interpretation of their own instructions. It is also clear that situations arise in which “tests of will” take place between relatively junior officers on both sides, in the course of which the temptation to “shade” their instructions is undoubtedly very strong.

I have no solution to offer but suggest that when incidents do occur, you will want to satisfy yourself that the investigation on our part does not become just routine but that we thoroughly satisfy ourselves that our Commanders are rigidly adhering to their instructions in these [Page 413] matters of such great moment. I would also be glad to consider any suggestions that you may have for a broad approach to the Soviets on this question or any other suggestions that you may have.3


  1. Source: National Archives and Records Administration, RG 59, Central Files 1964–66, POL 33–6 USUSSR. Secret.
  2. Not printed.
  3. Vance responded in a November 30 letter to Kohler, Johnson’s successor, stating that “yielding a clear right in any operational situation only invites future trouble” but that “pressing a situational advantage beyond reasonable or accepted rules of encounter risks serious damage to the delicate fabric of US-Soviet relations.” Vance proposed “that the United States attempt to reach an understanding with the Soviets” on the issue. (National Archives and Records Administration, RG 59, Central Files 1964–66, POL 33–6 USUSSR)