Unequal We Fight: Between- and Within-Group Inequality and Ethnic Civil War

When and why ethnic groups rebel remains a central puzzle in the civil war literature. In this paper, we examine how different types of inequalities affect both an ethnic group’s willingness and opportunity to fight. We argue that political and economic inter-group inequalities motivate ethnic groups to initiate a fight against the state, and that intra-group economic inequality lowers their elite’s costs of providing the necessary material and/or purposive incentives to overcome collective action problems inherent to rebel recruitment. We therefore predict that internally unequal ethnic groups excluded from power and/or significantly richer or poorer relative to the country’s average are most likely to engage in a civil war. To assess our claim empirically, we develop a new global measure of economic inequality by combining high-resolution satellite images of light emissions, spatial population data, and geocoded ethnic settlement areas. After validating our measure at the country- and group level, we include it in a standard statistical model of civil war onset and find considerable support for our theoretical prediction: greater economic inequality within an ethnic group significantly increases the risk of conflict, especially if political or economic inequalities between groups provide a motive.