On the theory of ethnic conflict

We present a theory of ethnic conflict in which coalitions formed along ethnic lines compete for the economy's resources. The role of ethnicity is to enforce coalition membership: in ethnically homogeneous societies members of the losing coalition can defect to the winners at low cost, and this rules out conflict as an equilibrium outcome. We derive a number of implications of the model relating social, political, and economic indicators such as the incidence of conflict, the distance among ethnic groups, group sizes, income inequality, and expropriable resources.