Four and a half decades ago, President John F. Kennedy publicly mused about the possibility that fifteen to twenty-five countries would have nuclear weapons by the 1970s. This did not materialize, and it still has not. That such a worrisome scenario has not yet come to pass, however, provides no assurance that it will not still occur. The proliferation of nuclear or other unconventional weapons is a prime example of a security issue in which the seeds of threatening developments are always present, even though the circumstances that would cause some of those seeds to sprout are unpredictable.
Kennedy's comment should be remembered chiefly for underscoring three truths. First, proliferation of weapons capable of causing mass destruction has long been a matter of high concern and a priority of public policy. For the same reason, it is likely to continue to be a high-profile issue. Second, uncertainty in this subject abounds, and prediction is foolhardy. Kennedy wisely was not venturing a prediction but instead speaking about possibilities. And third, the future, predicted or not, can be shaped through policies, wise or not. The darker possibilities of unchecked nuclear proliferation did not materialize in the 1970s partly because of international efforts at arms control in the 1960s. These included a treaty to ban nuclear testing in the atmosphere, completed during Kennedy's presidency, and the Nuclear Non-Proliferation Treaty, which was signed later in the decade.
Public concern and policy deliberations will continue to be focused not only on weapons proliferation itself but also on efforts to reduce the inevitable uncertainty to a minimum and to form more accurate images of foreign programs to develop nuclear and other unconventional weapons. This inevitably will mean a focus on intelligence. Large—often unrealistically large—expectations get placed on intelligence to produce precise pictures of foreign programs. Such pictures are typically difficult to draw, partly because the programs are