External support in civil wars can lead to cohesive and strong rebellions, or fragmented rebellions afflicted by internecine violence. What factors account for this variation? To understand this, I answer two related research questions: (1) why do states provide different forms of external support to rebel groups in civil wars and (2) how do different forms of external support shape intra- and intergroup rebel dynamics? I explore the range of ways in which a state can intervene to support non-state actors fighting the government of a state. As researchers increasingly appreciate the importance of disaggregating conflict actors in space and time, a similar trend is emerging in research on external support. I take a broad definition of external support in order to better understand the strategic logic of providing different forms of support. support ranges form financial and military equipment to boots on the ground—i.e. the full spectrum from covert support to what is commonly referred to as proxy conflict and direct military intervention.
To account for how the international environment shapes subnational conflict dynamics, I make a two-step argument. First, I argue that some states provide low risk forms of support such as money and weapons in order to avoid detection and punishment. They do this because they expect costly retaliation from the target—the government that the rebels are fighting—or its allies. Other states do not expect retaliation or are confident that it will not be costly. Different forms of support have different effects on the conflict environment and rebel dynamics at the intergroup and intragroup levels. While some support tips the balance of power to cause bandwagoning among and within rebel groups, other forms causes competitive relations among rebels. Therefore, different forms of support leads to rebel compeittion or cooperation.
I adopt a nested research design to test this theory. First, I conduct temporal network analysis of external state support, rebel fighting and rebel alliances from 1989 to 2009 drawing on UCDP data. Second, I employ process tracing of external support and rebel dynamics in (1) Northern Ireland during the recent conflict–known as the ‘Troubles’–from 1968 to 1998 and (2) the Algerian civil war from 1992 to 2001. In a final chapter, I compare the civil wars in Syrian and Libya using geo-located event data.