235. Memorandum From the President’s Special Assistant for Science and Technology (Wiesner) to President Kennedy0

The attached preliminary report by the Foreign Weapons Evaluation Group, a committee of weapons experts from Los Alamos and Livermore under the chairmanship of Dr. Hans Bethe, evaluates the results to date of the 1961 and 1962 Soviet nuclear weapons test series.1

The report indicates that the same group significantly over-estimated Soviet capabilities in its original review of the data on the 1961 Soviet test series. On the basis of data from the current Soviet series, including a new source of information from close in electromagnetic signals and a re-evaluation of data from the 1961 series in the light of current knowledge, it is now concluded that the Soviets are probably [6-1/2 lines of source text not declassified].2 The group has also concluded that the tests in the 1962 Soviet series do not involve any substantial advances over the 1961 series and that a large number of them appear in fact to be repeats of the 1961 tests, presumably in weaponized versions. The new data continues to highlight the fact that the U.S. has a substantial technological lead in the thermonuclear weapons [less than 1 line of source text not declassified].

These conclusions which have been agreed to by senior scientists from the Livermore and Los Alamos Laboratories and the RAND Corporation are considerably at odds with the views of Dr. Teller who, as the attached newspaper article indicates,3 has undertaken a program of public education on the status of U.S. and Soviet weapon capabilities. He has access to all classified weapons data, presumably the analysis on which this report was based.

  1. Source: Kennedy Library, National Security Files, Bromley Smith Safe, Drawer 1, Bethe Report 10/4/62. Top Secret.
  2. The attached 6-page “Report of the Foreign Weapons Evaluation Group Meeting of 2-3 October 1962,” dated October 4, is not printed. See the Supplement.
  3. For a summary of the previous Bethe report, November 17, 1961, see Document 96.
  4. The attached, unidentified newspaper clipping, not printed, contains a United Press International story in which Dr. Edward Teller, Associated Director of the Lawrence Radiation Laboratory at the University of California, expressed criticism of the U.S. nuclear testing program and said, among other things, “It is my guess, and it is only a guess, that the Russians are ahead of us in the nuclear race today.”