Uneasy Lies the Crown: External Threats to Religious Legitimacy and Interstate Dispute Militarization

Although often argued that religion should significantly influence international conflict, the empirical record is mixed. For every recurrent interreligious conflict, there are numerous examples of sustained interreligious cooperation. Conflict also frequently mars the oft-assumed peaceful relations between shared-religion states. We argue that religion is an important intervening factor in interstate dispute militarization, especially between internally threatened rivals. In mixed-religion dyads, conflict often follows oppression of cross-border coreligionists, whereas in shared-religion dyads, conflict occurs as one side disproportionately increases its official support for that religion. In both instances, dispute militarization is primarily an effort to undercut domestic competitors, whose challenge is augmented by external threats to leaders’ religious legitimacy. We test these propositions using new, long-term data on religious demography and state-religion policy, identifying rivalries via antecedent interstate territorial disputes. The findings largely confirm our hypotheses, substantially clarifying the conditions under which religion contributes to international militarized conflict.