International Orders and the Return of War

International orders have never eliminated war, but they have shaped its forms, legitimacy, and intensity. This essay traces the relationship between international order and organized violence from early modern Europe to the present, arguing that the post–Cold War decline in interstate war represents a historically contingent interlude rather than a durable transformation. The liberal international order after 1990 combined universalized sovereignty, liberal norms, strong international institutions, and US hegemony, thereby constraining large scale war while remaining highly selective. Since the mid 2010s, however, authoritarian resurgence, domestic populist backlash, institutional erosion, and Russia’s war against Ukraine have hollowed out this order. Rather than converging on a single successor, the international system now confronts an open future shaped by three plausible pathways: renewed bipolar conflict, a fragmented triadic order, and a thinned out form of global governance focused on managing interdependence without liberal normative ambition. Each entails distinct risks for peace and stability.