148. Memorandum From the Chairman of Joint Chiefs of Staff (Brown) to Secretary of Defense Brown1


  • Comprehensive Test Ban Issues (U)

1. (C) The purpose of this memorandum is to transmit the views of the Joint Chiefs of Staff on the Comprehensive Test Ban (CTB) issues and to provide a basis for the DOD response to PRM/NSC–16.2

2. (S) After a careful review of the Interagency Working Group’s response to the PRM,3 the Joint Chiefs of Staff have concluded that, although the facts developed in the response do not support a CTB at this time, the presentation of the substantive issues in the Executive Summary could result in misleading conclusions upon which future US security policy and negotiating strategy may be based. It is, therefore, essential that these issues be clarified. The issues of utmost importance concern the impact of a CTB or moratorium on US military capabilities and the adequacy of US intelligence capabilities both to ascertain the status of Soviet weapons programs and to monitor compliance with a CTB agreement.

3. (S) The Joint Chiefs of Staff recognize the longstanding US policy regarding a comprehensive ban on nuclear testing within the context of an adequately verified agreement, including the commitments made in the Limited Test Ban Treaty (LTBT), Non-Proliferation Treaty, and Threshold Test Ban Treaty (TTBT). It must be pointed out, however, that this policy was developed at a time when the United States was in a position of clear strategic superiority. Presumably, a CTB at that time would have slowed the rate at which the Soviet Union could have improved its strategic forces and would have delayed the point at which it could have achieved parity. The strategic situation has changed drastically in the last few years, and, although there are differing opinions as to the relative military advantages held by either the United States or the Soviet Union in specific areas, it is generally agreed that the two powers are now in a state of overall rough equivalence.

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4. (S) Whether the trend of increasing strength of the Soviet Union relative to the United States will taper off in the future is a matter of considerable debate within the Intelligence Community; [3 lines not declassified] It is impossible to project the threat which may now be developing and which may not be clearly perceived by the United States until such time as a CTB would make it difficult or impossible to respond.

5. (S) Current US force improvement initiatives have been taken primarily to respond to threats which have been postulated with some certainty. A CTB agreement will limit US ability to develop military systems which are essential to respond to these postulated threats. It is recognized that a CTB which includes prohibition of peaceful nuclear explosions (PNEs) will constrain the Soviet Union’s ability to develop new initiatives. However, the Joint Chiefs of Staff emphasize that a CTB may render the United States virtually unable to respond to the future threat which may now be developing and, thus, is unconstrained by the effects of a CTB.

6. (S) National policy calls for development and maintenance of a deterrent and warfighting capability across the spectrum of warfare, ranging from strategic nuclear offensive and defensive operations through tactical nuclear, conventional, and unconventional operations. To support this policy, the existing strategy provides for forces which are highly selective, effective, flexible, and responsive to the requirements of the National Command Authorities. By continuing a strong technological capability made possible under the constraints of the LTBT through the maintenance of a viable underground test program, the United States has continued the development of nuclear capabilities which will assist in the fulfillment of national policy objectives. However, without the present underground testing capability, the US Armed Forces could not confidently exploit advanced nuclear weapons development technology or nuclear weapons effects technology to provide these capabilities nor could they assure the reliability either of new designs, of older nuclear weapons which have been stockpiled over long periods of time, or of replications of older tested designs. Therefore, the Joint Chiefs of Staff believe that, for the foreseeable future, continued nuclear testing will be necessary.

7. [1 paragraph (23 lines) not declassified]

8. (S) In the view of the Joint Chiefs of Staff, the adequacy of verifying a CTB agreement is dependent on the ability unequivocally to assure the national authorities that no potential adversary is achieving military benefits through nuclear testing. Although the PRM–16 response points out that improvements to US national technical means could reduce the likelihood of undetected tests, the Executive Summary [10 lines not declassified]

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9. (S) The Executive Summary overemphasizes the probabilities that the leadership of the Soviet Union would be unwilling to conduct an evasion program. In the past, the United States has officially notified the Soviet Union of 21 violations of the LTBT, but all charges have been denied by the Soviet Union. There is also some question by experts in the United States about two Soviet detonations which may have exceeded the 150 kt limit in the informal understanding regarding the TTBT. It is recognized that these instances may be considered by some as of a different nature than a violation of a CTB. However, it must still be pointed out [3 lines not declassified] that even when clear evidence of a violation exists, any charges against the Soviet Union may be meaningless.

10. (S) In view of the above, the Joint Chiefs of Staff believe that a CTB is not in the best interests of the United States at this time because of:

a. The potential adverse effect on military capabilities caused by US inability to develop military systems required to respond to current and future threats, US inability to maintain a nuclear weapons technology base, and US inability to insure continued nuclear systems reliability.

b. The known limits on US verification capabilities.

c. [2 lines not declassified]

d. [2½ lines not declassified]

11. (S) If a decision is made to proceed with negotiations for a CTB, the Joint Chiefs of Staff consider the following points to be pertinent:

a. An unverified or unilateral moratorium should be avoided.

b. Nuclear testing should continue during CTB negotiations, and the effective date of a CTB should be selected so as to permit the completion of testing for key systems. Although some systems now under development might be placed in the stockpile without further planned testing, it would be at the cost of significantly reduced effectiveness and reliability. It should be noted that testing [4 lines not declassified]

c. [1½ lines not declassified]

d. PNEs should not be permitted in a CTB environment. Despite a lengthy exploration in the PRM–16 response to find ways of accommodating PNEs in a CTB with minimum risk to national security, there appears to be no feasible way to prevent military advantages accruing from the conduct of PNEs.

e. All nuclear powers should eventually be signatory to a CTB. In the short term, only the Soviet Union threatens US security. However, long-term advances by the PRC or other countries also could become a factor. Therefore, any cessation of testing must allow for periodic review and a clear opportunity to renew testing if all nuclear weapon states do not adhere within a reasonable period of time.

f. The TTBT and Peaceful Nuclear Explosions Treaty should be ratified as soon as possible.

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12. (U) The Joint Chiefs of Staff request that you consider their views in concluding your review of PRM/NSC–16.

For the Joint Chiefs of Staff:

George S. Brown
Joint Chiefs of Staff
  1. Source: Washington National Records Center, OSD Files: FRC 330–80–0017, Box 63, A–400.112 Test Ban (5 Mar 77) 1977. Secret. Copies were sent to the Director of the Defense Intelligence Agency (Tighe) and the Director of the Defense Nuclear Agency (Johnson).
  2. See Document 141.
  3. See Document 146.