What Do Nuclear Weapons Offer States? A Theory of State Foreign Policy Response to Nuclear Acquisition

Abstract

How do nuclear weapons change the foreign policies of the states that acquire them? This paper offers a theory, labeled “nuclear pragmatism,” that explains the origins of six foreign policy behaviors that nuclear acquisition may facilitate — aggression, expansion, independence, bolstering, steadfastness, and compromise. While nuclear weapons may facilitate each of these behaviors, different states have different goals in international politics, and different combinations of behaviors are thus attractive to different states. The theory argues that three independent variables are important in determining which of these behaviors states are likely to use nuclear acquisition to facilitate, and thus condition the effect of nuclear acquisition. These variables are (1) the presence of severe territorial threats or an ongoing war with a peer competitor; (2) the presence of allies that provide for the state’s security; and (3) whether the state is increasing in power relative to its primary rivals. I illustrate the theory with empirical examples of the different theoretical pathways identified, and make predictions for the changes in foreign policy that should be expected if Iran were to acquire nuclear weapons.