The Provision and Impact of External Military Support to Combatants in Civil War

Abstract

External support has been a prominent feature of many internal conflicts during the past half-century. Existing literature has often cited external support as playing a key role in these conflicts. The many high quality recent works looking at external support reflect this realization. Despite this, a number of important questions about external support remain unanswered. This dissertation addresses three important unresolved questions through three different papers. These questions reflect three broad issues of concern: (1) When is external support likely to occur? (2) What impact does external support have on combatant capabilities? (3) To what extent is a supporter able to influence a combatant? Existing work has highlighted the important role that combatant capability plays in influencing the occurrence of support. Combatant capabilities, however, are not likely to have the same impact on the provision of support regardless of the reason why a supporter would become involved. The first play theorizes about this issue as well as conducts preliminary analysis using new time-varying data of when support is likely to be provided. Similarly, although the influence of external support has largely been assumed in existing academic work—and given limited testing—much recent policy work casts doubt on this influence. Using new disaggregated data on combatant capabilities and the provision of external support, the second paper seeks to identify the impact of support. Support, broadly, is found to heavily impact the ability of rebels to produce large capable forces that are protected from state attacks; this impact, however, depends on the type of support provided. Finally, a main concern for supporters is that they are able to influence the behavior of particular rebel groups. Using supporter influence over rebel use of one-sided violence as an indicator of supporter ability to influence, paper three develops and tests a theory of the conditions required for influence to occur. For influence to occur, a rebel must be reliant on the supporter, the supporter should not be reliant on the rebel, and the supporter must have an incentive to spend resources to exert control.