Prominent academic theorists and policy analysts have argued that the spread of nuclear weapons is perhaps compatible with international stability. The arguments, although against the grain of official U.S. government policy during and after the Cold War, have a strong appeal. Optimists about proliferation base their case on rational deductions from theory and on their interpretation of U.S. and other Cold War experience. If these arguments are valid, then U.S. government strategies for controlling the spread of nuclear and other weapons of mass destruction (WMD) may be misguided. Instead of promoting a “one size fits all” policy of prevention, the U.S. should acknowledge the inevitability of (at least) selective nuclear proliferation and promote the creation of stable regional balances of terror.