Testing theories of alliance formation: the case of Southwest Asia

The question “what causes alignment?” remains a basic issue in international relations theory. Moreover, competing hypotheses about alliance formation underlie many recurring policy debates. Balance-of-power theory predicts states will ally to oppose the strongest state; the “bandwagoning hypothesis” predicts that alignment with the stronger side is more likely. These two hypotheses are usually framed solely in terms of the distribution of capabilities (that is, the balance of power), which neglects several other important factors and leads to faulty predictions about alliance choices. A careful examination of the alliance policies of Iran, Turkey, India, and Pakistan reveals that “balance-of-threat theory” provides a better explanation of alliance choices than these other conceptions. This theory predicts that states balance against the most threatening state, rather than the most powerful. Threats are a function of power, geographic proximity, offensive capability, and perceived intentions. Thus, balance-of-threat theory is an important refinement of structural balance- of-power theory.