711.5611/6–454
The Secretary of Defense (Wilson) to the Secretary of State
Dear Mr. Secretary: Replying to your letter of May 261 posing certain questions concerning the possible technical and propaganda advantages of a limited moratorium on future tests of nuclear weapons, I advise you that the Department of Defense feels that there is no compelling reason which would require this Department to modify its position previously expressed to you in my letter of May 17.2
With regard to the specific questions in your most recent letter, I advise you as follows:
1. It is our judgment that limitation by effective agreement of future experimental explosions to a fixed upper yield would not be to the technical advantage of the United States. This view is based upon the best scientific advice available to us, which would indicate that until an acceptable formula for the elimination of nuclear weapons from the armaments of all nations can be devised and implemented, the security of the United States will depend in a large measure upon continued and intensive application of our scientific engineering and industrial capacity in this field without being circumscribed as proposed.
We realize that the proposed limitation might be acceptable if such a limitation agreement held promise, either through a propaganda advantage or otherwise, of such an overriding and advantageous nature as to justify some diminution of scientific development that would follow the proposed limitation. It is our judgment that the proposed moratorium does not hold such promise.
2. We do not believe that the technical disadvantage of a limited moratorium would be overcome by any propaganda advantage. As I have stated above, we believe that such a propaganda advantage should be very clear and of sizeable proportions in order to justify a moratorium that would impede to some extent our own progress. On the contrary, we believe that the USSR would likely seize and expound upon any agreement by us as being motivated by a desire to limit Russian progress. The USSR could also charge us with violations and produce faked evidence in proof which we could not [Page 1458] refute without revealing vital information. It is my understanding that with the experience of the recent tests behind us our scientists believe that we can so govern the magnitude and nature of future experimental explosions as to avoid the risk of seriously harmful effects on others.
3. It is not possible technically to set up arrangements which would dependably expose any violation of an agreement to limit the magnitude of explosions without the full cooperation of the agency actually conducting the tests. With respect to the reliability of remote detection methods the best estimates by our own scientists are at wide variance. Some believe we can estimate the yield of a Soviet explosion within 30 per cent; others feel that we cannot expect to do better than a factor of 2 to 3. Should the USSR elect to detonate a high yield device at some remote location outside the USSR, such as in the Antarctic, our ability to detect the occurrence of the explosion as well as to determine the yield would be greatly depreciated.
4. Inasmuch as it is not possible to answer questions 2 and 3 in the affirmative, I see no logical or public relations stopping-point between “no top limit” and “total abolition”. Assuming, however, that these questions could be answered affirmatively and that the USSR should see an advantage in accepting a limited moratorium, there appears no way of avoiding continued pressure for lower limits down to abolition by agreement only. Clearly, a limited moratorium could be the first step in the direction the USSR is attempting to lead the world.
Sincerely yours,