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.