Civil wars are widespread and devastating. Third-party involvement by foreign states strongly influences the course and outcome of these conflicts. This dissertation advances our knowledge about why civil wars arise in the first place and why foreign states get involved. First, the dissertation sheds new light on factors that shape the likelihood of third-party involvement by pointing to two interrelated domestic-level determinants: political institutions and public opinion. It demonstrates that democratic institutions constrain decisions about third-party involvement in civil wars by analyzing various types of third-party support from foreign states to civil war actors. The dissertation then digs deeper into this relationship by investigating the role of emotions in shaping citizens’ sensitivity to the costs of conflict. Second, the dissertation advances our knowledge about factors that shape the risk of civil war by investigating potential third-party involvement and historical third-party involvement. It demonstrates that uncertainty about potential third-party involvement caused by irregular leader changes among neighboring countries increases the risk of civil war. Furthermore, it shows that historical third-party involvement in the form of European colonization in conjuncture with higher levels of precolonial state development also increases the risk of civil war. Overall, the dissertation highlights that policymakers and researchers should take both the causes and consequences of third-party involvement into account to gain a better understanding of the complex phenomenon of civil war. The dissertation is of relevance to all who are interested in causes of armed conflicts and foreign policy concerning such conflicts.

Download pdf