FIRST-STRIKE STABILITY IN A MULTIPOLAR WORLD

First-strike stability in a multipolar world measures the incentives o f all major nuclear weapon countries, in all possible coalitions, to r efrain from preemptive attack. The analysis integrates the interaction s of offensive weapon arsenals, vulnerable offensive weapons within th ese arsenals, defensive weapons, and value targets reflecting the nati onal assets at stake. In the previously-dominant bipolar paradigm, whe n the United States and the Soviet Union possessed almost all of the s trategic nuclear weapons in the world, first-strike stability was an i mportant criterion for assessing defensive deployments of the two side s, without consideration of any other countries. In the emerging multi polar world, however, the United States and Russia are dramatically re ducing their offensive forces, and the offensive arsenals of Britain, France, and China are becoming relatively more important. Also, prolif eration of medium-range ballistic missiles to other countries capable of attacking Russia, Britain, France, and China, but not necessarily t he United States (due to range limitations), greatly complicates the o verall situation. The main thrust-of this paper is to investigate the first-strike stability implications of the deployment of strategic def enses by the United States and Russia. The principal finding is that i n a multipolar world first-strike stability increases with the deploym ent of small to medium sized strategic defenses whereas in a bipolar w orld it usually decreases. Although the incentives for the United Stat es and Russia to preempt increase, the incentives of the other countri es decrease, with the combined effect over all coalitions of decreasin g the incentive to preempt.