Summary

The international arena has been plagued with violence committed by a variety of Nonstate Armed Groups (NAGs), including ethnic and religious insurgents, terrorists, and revolutionaries, which threaten not only the states they target but also the entire world’s stability and security. An intriguing observation related to armed groups is their ability to attract outside state supporters. Indeed, almost half of all groups that emerged in the post-World War II period received some form of backing from states including but not limited to funds, arms, and safe havens. In this respect, it is possible to draw parallels between interstate alliances and state–group alliances. The major International Relations theories—realism, liberalism, and constructivism—have significant insights to offer in explaining the origin and evolution of state–rebel group alliances. These insights are empirically tested using new data on outside state support of rebel groups that emerged in the post–1945 period. Two forms of alliances exist between states and groups: strategic or instrumental and principled or ideational. A strategic alliance occurs if a state supports a group fighting against its enemy or rival, so security-related concerns and common threat motivate a given alliance. An ideational or principled alliance occurs if a state supports an ideationally contiguous armed group with which it has ethnic, religious, and/or ideological ties. Whether there is a strategic or principled alliance between armed groups and their state supporters has implications for the onset, course and termination of non-state violence in world politics.

The empirical findings using large-N statistical analysis show that (1) states form alliances with rebel groups in both the absence and presence of interstate hostilities; (2) states form alliances with ideationally contiguous rebel groups, that is, groups that have common ethnic, religious, and ideological ties to states’ population and/or a group of people in its society; (3) democratic states do not ally with rebels, which fight against other democratic states; and (4) states, in general, are less likely to support rebels, which fight against ideationally contiguous states. Socialism emerges as a unifying ideology contributing to a high degree of solidarity both among states and between states and armed groups. The empirical findings imply that the perceived motivation of state supporters by armed groups; whether states support rebels due to strategic or ideational concerns, should have some influence on armed groups’ level of lethality, duration, and attitude toward civilians and governments they fight against. Only a fully developed research agenda offering empirically informed theoretical insights can address these questions by facilitating future venues of research on the origin and evolution of state–NAG alliances.