How much does the antiquity of states, and the sometimes arbitrary nature of colonial boundaries, explain why some states are more susceptible to civil conflict than others? Older states and those with greater historical legitimacy (more continuity between the pre-colonial and post-colonial state) have less ethnic diversity. Controlling for a lack of historical legitimacy, ethnic polarization adds to the risk of conflict, but a short history of statehood does not. The degree of political organization of ethnic groups or their exclusion from political power does not significantly affect the risk of conflict.
