How do international politics influence the outbreak of civil wars? While many scholars think there is an intuitive connection between international politics and the risk of civil war, my dissertation provides the first systematic account of the shape of this relationship. Governments and opposition groups in civil conflicts often leverage international influences in their domestic conflicts, and states are often willing to supply support in pursuit of their own ends. My dissertation asks, When does an increase in the potential supply of foreign support increase the risk of a civil conflict escalating to war? More generally, how do conflicts beyond a state’s border influence the incentives of actors in domestic conflicts to compromise, repress, or escalate?

I use interstate rivalry as an entry point for theorizing how interstate conflict contributes to civil war escalation in other states. When states associate the foreign-policy orientation of other states with their own security, they are more easily drawn to adopting a proxy in civil conflicts. Rivals’ competitive relations make them wary of the spread of their adversaries’ influence, especially in nearby states, and they often intervene to bend the policies of participants and the outcome of the conflict in their favor and away from their rivals’. This potential supply of foreign support encourages increased polarization amongst civil conflict actors as they make themselves more attractive as proxies, in turn making intervention more attractive by raising the stakes of the conflict for the rivals.

I further develop this theory in a formal model of civil conflict bargaining with two interveners. A key result of this model is that more closely matched rivals are particularly destabilizing to states in their neighborhood. I test the implications of the model using novel data on the spatial distribution of rivalry and interstate conflicts. I use case studies of Lebanon in 1958 and Syria in 2011 to further test the implications of the theory.



Rivalries and repression

In related projects I examine how interstate conflict influences some precursors to civil war: patterns of repression, exclusion, and political violence. Rivalries provide states with a justification for cracking down on opposition groups and excluding groups who are seen as potential threats due to their links–real or imagined–with foreign states. In a large-n analysis, I find robust support that being in a rivalry increases levels of domestic repression. I provide a further test in a case study of Yemen.

Foreign support and rebel group fragmentation

Foreign support for rebellion has largely been treated as the same as other resources in the study of rebel group behavior in civil wars. Unlike other resources used to fund rebel groups, foreign support often comes with conditions attached and rebel factions can position themselves ideologically and strategically to secure resources from actors abroad. In this project I argue that conflict beyond a states borders can contribute to the fragmentation of groups engaged in rebellion. Conflict between nearby states gives the incentive to (potential) rebels to make themselves attractive as proxies and the supply of foreign support makes it possible for new or splinter groups to form. I use data on the spatial density of interstate conflict and the emergence of new groups in civil wars to test these claims.