This estimate updated an estimate (NIE-4-2-64) published in 1964 of the nuclear proliferation problem. That estimate, like this one, overestimated the likelihood of an Indian bomb, while somewhat underestimating Israel’s program. This assessment followed the same pattern—predicting India would produce a weapon within a “few years” and also putting Israel in the “might” category, although treating it as a “serious contender” nonetheless. Also following a short discussion of the “snowball effect” (later known as “proliferation cascades” or “chains”) suggesting that the United Arab Republic (Egypt-Syria) and Pakistan were likely to take the nuclear option should India or Israel go nuclear.

This US analysis of the likelihood of nuclear proliferation during the next decade was finished only days after the first Chinese nuclear test on 16 October. The report analyses the implications of this test, as well as programs in India, Israel, Sweden, West Germany, Italy, Japan, Canada, and others. The National Intelligence Estimate (NIE) argued that India was the only new state likely to develop nuclear weapons, concluding that “there will not be a widespread proliferation …over the next decade.”

Noting new intelligence information on the Indian and Israeli nuclear programs, as well as the possibility of developments concerning Sweden, Hughes requested McCone to initiate a new estimate of nuclear proliferation trends, which would eventually become part of a October 1964 National Intelligence Estimate (NIE). Hughes enclosed draft “terms of reference,” that included questions about the possibility of “clandestine” weapons programs and new technological developments that could make weapons development “easier” (perhaps a reference to gas centrifuge technology that the 1964 NIE would discuss).

This NIE comes to the general conclusions that “there will not be a widespread proliferation of nuclear weapons over the next 10 years” and discusses programs in various countries (Israel, China, Sweden, India, West Germany, Japan, etc.) This copy includes newly declassified references to the Israeli nuclear weapons program, including the conclusion that “the Israelis, unless deterred by outside pressure, will attempt to produce a nuclear weapon some time in the next several years.”