The two swords

Since the end of the Cold War, a global religious resurgence has transformed many aspects of world politics, including transnational activism, human rights, and terrorism. Yet, scholars still debate whether a generalizable influence of religion on interstate disputes exists. Despite significant progress in the study of religion and world politics, then, the fundamental question remains: under what conditions does the post-Cold War era’s religious resurgence influence interstate disputes? This article points to the significance of institutional religion–state connections and ideological distance between disputants to account for the varied significance of religion in interstate conflicts. Religion influences conflict behavior when there are close ties between religion and the state and when a religious state is in a dispute with a secular state, creating ideological distance between the combatants. In such instances, the dispute is more likely to involve the use of force. The article tests this theory through a quantitative analysis of interstate disputes, using a Heckman probit model for the effects of religion–state connections on dispute severity. The tests reveal that while religious–secular dyads do not experience greater risks of conflict compared to other dyads, conflicts involving religious–secular dyads are more severe than those including other dyads, even when numerous competing explanations are accounted for. The article contributes to the study of religion and politics by highlighting the political factors that increase religious effects on international relations; it also contributes to the broader study of interstate crises by demonstrating the means through which ideas can affect interstate disputes.