Abstract:
The proportion of civil wars that involve external intervention has increased dramatically
since the end of the Cold War. So has the duration of such internationalized internal conflicts. This
thesis seeks to explain the relationship between these two phenomena by accounting for the
diversity of actors involved in civil wars. Existing research shows that multiple actors substantially
reduce the prospects for a negotiated settlement by introducing their own set of goals in the
conflict. Current civil war dynamics, however, show that parties involved in a conflict vary by the
types of their organizations. Building on the existing research, this thesis argues that types of actors
equally matter as they represent the diversity of goals that actors can pursue in civil wars. The
mixed-methods approach of the Cox proportional hazards model and a case study of the Yemeni
civil war demonstrates that greater diversity of actors leads to longer civil wars.