Why do rebel groups ally, and what makes some alliances more cohesive than others? This book develops an original typology of rebel alliances rooted in the identity of the armed groups involved, such as ethnicity and ideology, and the objectives they collectively pursue. Tactical alliances, oriented toward short-term, instrumental goals, require little more than momentary convergence of interest. Strategic alliances, by contrast, are based on shared transformative projects, such as regime overthrow. It is in these latter arrangements that cohesion becomes a central theoretical and practical concern. The book argues that establishing and implementing power-sharing mechanisms is crucial for determining the payoff structure available to coalition members and for raising the costs of defection, thereby sustaining cooperation under conditions of profound uncertainty. The argument is grounded in empirical analysis spanning two distinct conflicts. Drawing on the Syrian Civil War, the book examines how the typology's logic plays out across a fragmented and rapidly evolving conflict landscape, tracing the conditions under which different alliance types emerge. The question of cohesion is then addressed through an in-depth comparative analysis of two cases: the Syrian Democratic Forces in the Syrian Civil War (2011-2024) and the National Liberation Committee in the Italian Civil War (1943–1945). Together, these cases illuminate the conditions under which strategic alliances among rebel groups achieve durable cohesion in civil wars.

Edoardo Corradi is a Postdoctoral Research Fellow at the University of Bologna. His work focuses on rebel alliances and rebel governance in civil wars and has been published in outlets including Civil Wars, Small Wars & Insurgencies, Media, War & Conflict, Mediterranean Politics, Studies in Conflict & Terrorism, and Italian Political Science Review. He taught courses on Security Studies and International Relations at Sciences Po, Florida International University, and the University of Genoa.