Foreign Relations of the United States, 1964–1968, Volume XI, Arms Control and Disarmament

109. Memorandum From the Joint Chiefs of Staff to Secretary of Defense McNamara¹

JCSM-28-66

Washington, January 13, 1966.

SUBJECT

• Test Ban Proposals (U)

1. (S) In response to the request by the Deputy Assistant Secretary of Defense (ISA), I-28246/65, dated 23 December 1965,² subject as above, the views of the Joint Chiefs of Staff are provided on a memorandum by the Director, US Arms Control and Disarmament Agency (ACDA), to Members of the Committee of Principals, dated 17 December 1965, proposing a Threshold Test Ban Treaty (TTBT),³ as amended by a second memorandum, dated 29 December 1965, subject: “Addendum to December 17, 1965, Memorandum on ‘Test Ban Proposals’(U).”⁴

2. (S) A study by the Joint Chiefs of Staff of the Military Implications of a Comprehensive Nuclear Test Ban Treaty (CTBT) was forwarded by JCSM-348-65, dated 11 May 1965, subject: “Draft Message to Soviet Leaders on Disarmament (S).”4 Views of the Joint Chiefs of Staff on ACDA proposals for a comprehensive test ban and a threshold ban were forwarded by JCSM-601-65, dated 5 August 1965, subject: “Nuclear Test Ban Proposals (U).”⁵ Many of the previous views of the Joint Chiefs of Staff have relevancy to the current ACDA memorandum. The Appendix to this memorandum restates and amplifies previous positions of the Joint Chiefs of Staff which are germane to this issue.⁶

3. (S) The ACDA memorandum proposes that, at the resumption of the Eighteen-Nation Disarmament Conference (ENDC) on 27 January 1966, the United States attempt to negotiate a CTBT. In the event that the USSR is unwilling to permit the on-site verification necessary for a CTBT, the United States should then propose an extension of the present Limited Test Ban Treaty (LTBT) to underground tests with a seismic threshold of 4.75 without inspections. The views of the Joint Chiefs of Staff as expressed in the foregoing references concerning a CTBT remain valid and the Joint Chiefs of Staff believe that a CTBT would prejudice the national security interests of the United States at this time. The views concerning a 4.75 TTBT follow.

4. (S) The ACDA memorandum assumes that the United States could verify a threshold test ban using its existing national system and would rely heavily on unilateral US intelligence to identify suspicious events. The Joint Chiefs of Staff, as well as the United States Intelligence Board (USIB),⁷ have consistently stated that US intelligence capabilities should not be used as a primary means of verification of any arms control measure. Seismology, at best, can identify some seismic events as earthquakes; it cannot now identify seismic events as nuclear detonations. For these reasons the Joint Chiefs of Staff reiterate their position that a separate means of verification, including on-site inspections, should be established and in operation on the effective date of implementation of any such proposal.

5. (S) The Joint Chiefs of Staff believe that there will be inadvertent violations of such a treaty and many suspected violations because of the uncertainties and possible ambiguities associated with monitoring. For this reason, they believe that such a treaty may well create more suspicion than it dispels and may increase international distrust.

6. (TS) The Joint Chiefs of Staff consider that the effects of a TTBT upon the strategic nuclear balance may be sufficient to justify rejection of the ACDA proposal. The United States must approach any nuclear test ban from a position of strength. Although it may be accepted that the United States enjoys a favorable strategic position, this advantage is threatened by the deployment of a Soviet ABM system. To counter this threat, the United States must develop its own ABM system, must remove known vulnerabilities in US strategic missile systems, and must develop an advanced re-entry system, such as Multiple Individually-targeted Re-entry Vehicles (MIRVs). To realize these goals, tests beyond those permitted by the proposed test ban are required. [2-1/2 lines of source text not declassified]

7. (S) While ACDA acknowledges the importance of a hot X-ray ABM system, the argument set forth by ACDA appears to be that the USSR does not possess the needed know-how to exploit this potential capability and that further restriction, at this time, could freeze the USSR and US ABM race. The NIE statement, “there is no evidence that [1-1/2 lines of source text not declassified] is not sufficient assurance in this case. The USSR has had the opportunity to discover this and other effects under the present treaty as well as in their 1961/1962 high-altitude, high-yield tests. These latter tests might also have uncovered effects we know nothing about. We cannot assume that the USSR knows less than the United States about these effects.

8. (S) The Joint Chiefs of Staff recognize that there may be political advantages to the United States signing a TTBT, such as a limited impact on proliferation. However, there are important political disadvantages which, with the military disadvantages, are overriding in the view of the Joint Chiefs of Staff. They concur with the consensus of the Committee of Principals in the 25 August 1965 meeting in which it was noted that the imprecision inherent in monitoring such a treaty may lead to disputes, suspicion, acrimony, and distrust.

9. (S) On balance, the Joint Chiefs of Staff believe that the ACDA proposal would prejudice the security interest of the United States. Specifically, the Joint Chiefs of Staff are opposed to a threshold treaty as proposed because:

a. There are no provisions for policing a TTBT effectively.

b. Primary responsibility for verifying compliance with a TTBT would have to rest with Atomic Energy Detection System and US intelligence. The Joint Chiefs of Staff, as well as USIB, believe that these sources should not be relied upon for verification nor should they be so employed.

c. The inexactitudes of the science of seismology, as it applies to nuclear detonations, preclude a definite and unarguable policing of a TTBT. Such a treaty may lead to disputes, suspicion, acrimony, and distrust.

d. The TTBT would prevent the development of high-yield area defense ABM systems, as well as advanced re-entry warheads.

e. A TTBT would prevent rectification of serious vulnerabilities in existing US ballistic missile forces.

f. A TTBT would have a debilitating impact on the ability of the United States to maintain a competence in nuclear weapons technology.

10. (U) The ACDA memorandum states that a modalities paper for on-site inspection will be circulated for comment at staff level. The Joint Chiefs of Staff reaffirm their desire to make recommendations on any on-site inspection procedures prior to their being discussed, in public or in private, with foreign governments.

For the Joint Chiefs of Staff:

Earle G. Wheeler ⁸
Chairman Joint Chiefs of Staff

1. Source: Johnson Library, National Security File, Subject Files, Disarmament, 18-Nation Disarmament Committee (ENDC), Vol. II, Box 13. Top Secret; Restricted Data. A January 14 cover memorandum by R.C. Bowman, transmitting a copy of the source text to McGeorge Bundy, states that the Joint Chiefs of Staff “strongly oppose any new test ban proposal at this time,” because the likely Soviet development of an area anti-ballistic missile system could reduce the U.S. strategic deterrent capability to a dangerous level. The Joint Chiefs of Staff wanted continued testing for several years and at the same time improvement in detection capabilities to an adequate level for monitoring a test ban.
2. Reference is to a cover memorandum from Deputy Assistant Secretary of Defense Adam Yarmolinsky to Chairman of the Joint Chiefs of Staff Earle G. Wheeler requesting his views on the ACDA memorandum of December 17, 1965, to Members of the Committee of Principals, which proposed a Threshold Test Ban Treaty. (Washington National Records Center, RG 330, OSD Files: FRC 70 A 1266, 388.3 (2 Feb. 65), Nov.-Dec. 1965)
3. Not printed. (Ibid.)
4. Not found.
5. Not printed. (Washington National Records Center, RG 330, OSD Files: FRC 70 A 1266, 388.3 (2 Feb. 65), Aug. 1965)
6. Not printed.
7. TCS 3236/65/USIB-D-32/12/3; available in SAO channels. [Footnote in the source text.]
8. Printed from a copy that indicates Wheeler signed the original.