A recent National Security Strategy report singles out nuclear proliferation as one of the gravest threats to the United States. Much of this fear is focused on North Korea and Iran, two "rogue states" that have violated nonproliferation rules and engaged in provocative actions, including nuclear and ballistic missile tests. Conventional wisdom dictates that the regimes in these countries have a uniquely defiant and dangerous nature, and that coercive measures such as sanctions and preemptive strikes are the most effective way to deal with them. But how do the neighbors of these two states...