Nuclear proliferation is generally seen as a security problem, and decisions by states to develop nuclear weapons, or to prevent other states from acquiring them, are most commonly explained with at least some reference to the notion of “threat.” The idea that nuclear weapons are a response to a threat and themselves create threats for others is at the core of the “proliferation” concept, which is an amended version of the security dilemma: a mechanistic increase in states’ military capabilities provoked by a spiral of reciprocal fear and hostility. According to this conventional logic, “strategic-chain reaction” will take place because acquisition of nuclear weapons by a state is likely to provoke repercussions elsewhere, and the non-proliferation regime is the device states have found to tackle this problem. For most proliferation analysts, individual choices by states and their national identity do not matter greatly; what is most important is the geo-strategic position of states, their alliances, and the state of the international non-proliferation regime. Realists stress that states in a threatening environment will inevitably seek a nuclear security guarantee that can only be obtained through nuclearization or alliance with a nuclear power. Liberals are somewhat more optimistic and think that an effective regime can be decisive in avoiding a suboptimal situation of generalized proliferation. Nevertheless, both schools of thought share a common rationalist, utility-maximizing perspective about nuclear choices: states will balance between threats, rewards, and costs when considering nuclearization and/or adhesion to the non-proliferation regime. States that do not want nuclear weapons have every

incentive to join the nuclear non-proliferation regime and to strengthen it in order to avoid nuclearization by their neighbors. States that do want nuclear weapons will only join the regime to cheat and will try to violate it at a lesser cost and maximum benefit. Non-proliferation advocates thus concentrate their efforts on the strengthening of verification provisions in order to distinguish cheaters from honest participants.