50. Letter From President Kennedy to Prime Minister Macmillan0

Dear Mr. Prime Minister: We have been thinking some more about the test ban, and I have reached some conclusions I would like to share with you. We have come so far together that we want to be sure to keep as close as we can in the last stages of this effort.

I have had a study made of the possibility of clandestine tests by the Russians—and of the military importance such tests might have.1 The preliminary findings indicate that what we have all feared is the fact: we simply cannot be sure, without a control system, that the Soviets are not testing, and if they are testing, they can be learning important things. The final judgment of probabilities depends on a political assessment of the way the Soviets would estimate their own gains and losses from such a program, and I know of no one who has a right to a wholly certain judgment. We don’t know—but for the long run it is just this simple fact that is disturbing—in this field what we don’t know can hurt us.

Yet I remain most reluctant to take a firm decision to resume testing—the stakes are high and the consequences not easily predicted. So I propose to send Dean back to Geneva, about August 24, with instructions to make one more strenuous effort to move the Soviets. I do not see any need for a shift in our present negotiating position—it is clearer than ever that what is holding us up is the Soviet loss of interest in a treaty, as you pointed out back in April. But I think we ought to make one more try in Geneva just to bring home as well as we can the seriousness of the position the Soviets have created. I hope you may agree and that Ormsby-Gore may go back with Dean.

If Dean and Ormsby-Gore make no progress, we shall face the problem of further steps. We have already inscribed this question for discussion at the UN Assembly session, and I think we should use this and all other opportunities to press home the fact that the responsibility for failure rests with the Soviet Union. Incidentally, we shall shortly be publishing a paper on the test ban which has the same purpose.2 And perhaps, if the Berlin environment allows it, you and I should write a last letter to Khrushchev.

Meanwhile, I shall be forced to consider a decision to resume testing. I am still reviewing the evidence, and in any event I do not expect that [Page 131] there need be any U.S. tests in 1961. But I am not very hopeful that it will be possible to wait much beyond the first of the year. If we do resume, it will be underground, unless and until the Soviets resume atmospheric tests.

We are considering one further possibility, which is that at the UN and in a general campaign for some time thereafter—and before we resume testing—we should offer to join in an unpoliced agreement to give up all tests which can cause fallout. We believe that it may be possible to get wide public understanding of “fall-out testing” as bad, and underground testing as reasonable—and this would give us the assurance of parity with the Soviet Union which cannot exist at present. May I hear how all this strikes you?

Let me repeat my warm congratulations on your common market decision, and let me thank you too for your support of my Berlin speech—I tried to frame the language on civil defense so as to awaken our people without frightening yours.

With warm personal wishes,

Sincerely,3

  1. Source: Department of State, Conference Files: Lot 65 D 366, CF 1946. Top Secret. Transmitted to London in telegram 585, August 3, for delivery to Macmillan. (Ibid., Presidential Correspondence: Lot 72 D 204, Kennedy-Macmillan 1960-1962)
  2. Apparent reference to the Panofsky Panel report, Document 42.
  3. Not further identified.
  4. Printed from an unsigned copy that indicates President Kennedy signed the original.