Academics and international lawyers look for the sources of international law in the treaties and customs created by states. Although nonstate actors have often been subject to international legal rules, they have seldom been seen as having a role in the formation of such rules. International humanitarian law is no exception. The authors argue that this statist exclusion of nonstate actors from international lawmaking is outdated and normatively questionable. The authors suggest that nonstate actors-and specifically, nonstate armed groups-should be understood as potentially having a role in the making of international humanitarian law. Giving nonstate actors such a role would require academics and lawyers to look beyond the treaties and c...