Foreign Relations of the United States, 1961–1963, Volume VII, Arms Control and Disarmament

49. Letter From the Director of Defense Research and Engineering (Brown) to the President’s Special Assistant for Science and Technology (Wiesner)⁰

Washington, August 3, 1961.

Dear Jerry: In response to your letter of July 28, 1961,¹ the Secretary of Defense has asked me, in view of the short time available for response, to reply for him. I am also enclosing comments of the Joint Chiefs of Staff² on the report of your Ad Hoc Panel on Nuclear Testing.

I agree with the Panel that we do not have sufficient evidence from any source to determine whether or not the USSR has been conducting clandestine nuclear testing since November 1958.³ For this reason, it seems prudent to assume that they may have been doing so. Accordingly, I would add to the Summary, at the end of the second sentence in the second full paragraph on page 5 the phrase, “from whenever they start(ed),” and to the end of the Summary, page 6, the sentence, “It should be noted that the time scale should take into account possible clandestine activities by the USSR since November 1958.” The assessments of relative positions throughout the report, as on pages 15, 17, 24, 26, 27 and 32, seem to be accurate on the basis of 1958 data but do not indicate that the situation may be different now, as is clearly brought out in only one case on page 29.

The danger of closing off for a long period our own advances in nuclear weapons development, while the other side may continue, represents a greater risk if the arms race continues in other areas than it would if we could expect general arms limitation agreements. The Fisk Panel answered the questions about the technical and military effects of a test ban or a resumption of tests in the context that one possibility was a partially controlled agreement on nuclear testing, presumably to be followed by other agreements. Since the immediate prospects of arms limitation agreements seem more remote, the motivation for a Soviet violation of an unmonitored ban and consequent dangers to the U.S. appear greater.

Page 4 of the Summary points out that the significance of small pure fusion weapons depends on the extent to which future U.S. strategy emphasizes the use of nuclear weapons in tactical warfare. It also depends on future USSR tactics. If they emphasized such weapons and we did not have them, we could be at a distinct disadvantage, both militarily and politically.

On Page 4, also, the unfavorable cost ratio of Nike-Zeus to enemy ICBM’s is stated to be more significant than warhead performance or lack of knowledge of kill mechanisms. This is true. However, Nike-Zeus was designed to rely on known and conservative kill mechanisms and expensive warheads. If we knew more about the probable longer range lethal effects, the system might be quite different, and possibly much less costly. Furthermore, effects tests might show us how to reduce the vulnerability of our own ICBM warheads to a greater degree than we now believe possible. Thus, though my outlook for ballistic missile defense, at least of cities, is pessimistic, I believe that nuclear testing (and consequent warhead development) and better understanding of effects would have an important influence on both our ICBM penetration program and our AICBM efforts.

In summary, I find a stronger technical case for the resumption of nuclear testing than appears in the Ad Hoc Panel’s report. I would agree that delay of a few more months is unlikely to have a substantial military effect, but over the long run (including the nearly three years since October 31, 1958) possible Soviet gains from testing must certainly be considered an important military disadvantage to the U.S. Therefore, the position of the Department of Defense, as previously stated by Secretary McNamara, is that nuclear weapons testing underground should be resumed as soon as it is politically expedient. Secretary McNamara’s views were set forth more fully in the letter to Mr. McCloy dated July 28, 1961.⁴

Sincerely,

Harold Brown⁵

0. Source: Kennedy Library, National Security Files, Subjects Series, Nuclear Weapons, Testing. Top Secret; Restricted Data.
1. See the source note, Document 42.
2. Document 48.
3. In a memorandum to Wiesner dated August 3, Allen Dulles stated that the Panofsky Report’s conclusion that available intelligence permitted no conclusion with regard to Soviet clandestine testing was consistent with SNIE 11-9-61 (Document 17) and that “for the present we have no new important information to add to that presented in the Panel’s report.” (Kennedy Library, National Security Files, Subjects Series, Nuclear Weapons, Testing)
4. Document 47.
5. Printed from a copy that indicates Brown signed the original.