Birth legacies, state making, and war

International relations researchers study the interactions of states in the international system. Excluded from almost all such analyses is any consideration of how those states became members of the international system in the first place. State making researchers, in contrast, focus on the formation experiences of states. Drawing on insights from both approaches, we argue that states with positive birth legacies should be more successful at state making and achieve more favorable outcomes than states without positive birth legacies. As fighting and winning wars are a common pathway to political development, states with positive birth legacies should be more likely to participate in and win interstate and civil wars. Statistical analyses of all states in the international system from 1816 to 2002 support our expectations.