357. Editorial Note
On July 30, 1963, John McCone briefed the Joint Chiefs of Staff in response to questions raised by them concerning a test ban agreement. The Chiefs first asked what was the present position of the Soviet Union in relation to the United States in the fields of strategic nuclear weapons, anti-missile missile defense, and tactical nuclear weapons. According to McCone’s briefing paper, his response was that the Soviet Union [text not declassified]. The United States had more strategic weapons deployed. The Soviets did not exceed the United States in knowledge of the effects of multimegaton warheads on hardened missile sites.
In ABMs, neither side could be confident of the effectiveness of any ABM system chosen on the basis of present data, and hence any system widely deployed by either side was likely to be overdesigned to compensate for uncertainties, and hence more costly than one which would be attained through continued testing in the atmosphere and in space. The [Page 866] United States was presently superior in design, diversity, and numbers of nuclear weapons in most tactical systems. With unlimited underground testing, the Soviets would “over a period of years be able” to overcome the U.S. lead in weapons for tactical deployment and draw even. The briefing paper then detailed error rates in these estimates for different categories of weapons.
With regard to a question on U.S. detection capabilities for clandestine testing, the briefing paper stated that the United States could detect atmospheric tests of 5 KT or more. High yield tests could not escape detection except in deep space. A Soviet attempt to test underwater was unlikely.
Regarding Soviet motives in signing the limited test ban treaty, the most important, according to the paper, was the Soviet desire to achieve political gains in Europe by bringing about a general relaxation of tensions. The briefing paper also stressed a general Soviet desire to avoid proliferation, although not in China. The Soviets recognized that the treaty would not prevent China from attaining nuclear weapons and were unlikely to mount any preemptive strike against its future nuclear capability. They did wish, however, to demonstrate as part of their ideological competition with China that a Communist state could advantageously negotiate an agreement with a capitalist one. Another possible motive was an economic incentive to check the arms race and bring about a reduction of Soviet forces. (Memorandum from McCone to Bundy dated July 30, which covers two-section briefing paper of same date; Kennedy Library, National Security Files, Departments and Agencies Series, ACDA, Test Ban, U.S. Military Views)