This book investigates why some foreign powers that initially assist warring parties in civil wars later escalate to direct military involvement. The volume connects proxy war and direct intervention through a new theoretical framework, Support Escalation Theory, arguing that intervention (“direct support”) is risky and costlier than the transfer of resources (“indirect support”), and so is not chosen lightly. Using case studies, including Fascist Italy’s involvement in the Spanish Civil War in the 1930s and Russia’s intervention in the Donbas in 2014, the book highlights why foreign sponsors prefer to escalate from indirect to direct support: they do so when the time window to affect the conflict and avoid a negative outcome is running out, and the warring party would not be able to use further indirect support that would no longer be helpful. Therefore, foreign sponsors feel the incentive to step in with their own forces. Additional examples test how widely the pattern holds in the 20th and 21st centuries, shedding light on one of the most important—and dangerous—features of modern conflict. This book will be of much interest to students of civil wars, conflict studies, security studies and International Relations.
