Disproportionate recruitment of distinctive ethnic and religious groups has been a staple strategy of rulers throughout history. Why, however, do rulers limit their talent pool in this manner? Existing explanations have looked to irrational ideologies such as that of the 'martial races' or to a desire to maintain domestic power via a strategy of divide and rule amongst subject populations.

In this research, Charles puts forward an alternative explanation - that rulers preferentially recruit groups whose customary institutions are especially good at solving the social dilemmas inherent in fighting wars. Building on Iannaccone's club goods model, he argues that these customary institutions do so by serving two functions - screening out free riders ex ante and punishing them ex post. 
 

Dr Charles Miller is a senior lecturer in political science and international relations at the Australian National University. He received his PhD at Duke University in 2013 and has been working at the ANU since. His work has been published in World Politics, the Journal of Conflict Resolution and the Journal of Peace Research.