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

279. Memorandum From the Joint Chiefs of Staff to Secretary of Defense McNamara⁰

JCSM-327-63

Washington, April 20, 1963.

SUBJECT

• Nuclear Test Ban Issue (U)

1. A basic issue currently receiving wide attention is whether the US proposal for a nuclear test ban is, at this time, in the national interest. Those favoring a test ban claim that it is in the interest of the United States because they estimate that:

a. A test ban treaty would enable the United States to hold its nuclear technological superiority over the USSR.

b. A test ban treaty would bring about a net reduction of the risks faced by the United States and its Free World partners through a reduction of the dangers of proliferation and the continuance of the arms race.

Now that the provisions of the proposed test ban treaty appear to be crystallized, the Joint Chiefs of Staff deem it appropriate to summarize their position thereon.

2. Although the Joint Chiefs of Staff are not opposed to the concept of a fully effective test ban, they have, in the absence of provisions for effective verification of Soviet compliance, frequently expressed their concern with regard to the test ban issue. By JCSM-241-63, dated 21 March 1963, in commenting on an Atomic Energy Commission (AEC) draft paper, “US/USSR Weapons Capabilities Related to Possible Nuclear Test Ban Situations,”.¹ they recommended that more comprehensive examination be given to the many critical factors discussed therein before further commitments were made on a nuclear test ban treaty. To the knowledge of the Joint Chiefs of Staff, no such examination has ever been made and its omission constitutes a gap in test ban considerations.

3. [4 lines of source text not declassified] Most of these weapons components, particularly important for tactical uses on land and under water as well as for effective AICBMs, can be developed through underground tests that the Soviet Union could conduct clandestinely below our detection threshold. They will constitute a significant increase in military capability. [3-1/2 lines of source text not declassified] weapons are among many promising weapons developments discussed in JCSM-262-63, dated 3 April 1963, and JCSM-298-63, dated 16 April 1963.1 Effective AICBMs could make important targets much less vulnerable. If the United States is first to develop and deploy an effective AICBM, the likelihood of nuclear war, and destruction to the United States in the event of nuclear war, will be substantially reduced. Conversely, should the Soviets gain sole possession of an AICBM, they could increase substantially their military pressures on the Free World.

4. The Soviets have a substantial lead in very high-yield weapons because of their tests in ranges higher than those in which the United States has tested. US high-yield has been [less than 1 line of source text not declassified] USSR about 58 MT. The United States has conducted only [less than 1 line of source text not declassified] the USSR tested 34 large-yield devices in its last series alone. The Soviets also have more advanced knowledge of high altitude effects because of their recent more sophisticated tests. The United States is uncertain of Soviet capabilities in the low-yield range, principally because of our inability to detect and analyze low-yield tests. US inability fully to interpret data from Soviet tests, moreover, has caused some leading US scientists to believe the Soviets may have developed nuclear techniques beyond our knowledge. There is no reason to believe the Soviet Union could not, or would not, develop fusion and clean weapons clandestinely under the proposed nuclear test ban treaty. At this time, it is unlikely that any control system acceptable to the USSR can be expected to prevent such development. Only through an energetic test program in all environments can the United States achieve or maintain superiority in all areas of nuclear weapons technology.

5. It is apparent the Soviets will not agree to a test ban providing essential guarantees of verification and inspection to insure that clandestine testing cannot take place. The presently proposed US draft test ban treaty would provide a loophole for clandestine testing below the detection threshhold and thus would permit the Soviets to achieve significant weapons developments. In view of the significant and imminent weapons developments that would be denied the United States but could not be denied the Soviet Union under the proposed nuclear test ban treaty, the Joint Chiefs of Staff consider that the proposed test ban treaty, or any treaty without a detection threshhold under which the United States might legally test, would not, at this time, be in the national interest.

For the Joint Chiefs of Staff:

Maxwell D. Taylor²
Chairman
Joint Chiefs of Staff

0. Source: National Defense University, Taylor Papers, Comp Nuc Test Ban I, T-368-69. Secret; Restricted Data.
1. Neither printed.
2. Printed from a copy that indicates Taylor signed the original.