Introduction

The introduction presents the book’s central claim: major powers often intervene in civil wars primarily to deny rivals a foothold rather than to expand their own influence. Focusing on the United States and Russia across Syria, Libya, Yemen, and Sudan, it argues that the scale and style of intervention reflect perceived interests. When interests are high, intervention tends toward direct force and a durable presence; when interests are moderate, states rely on indirect tools, partners, private military companies, and focused diplomacy; when interests are low, engagement is minimal and episodic. The chapter motivates the theoretical logic of strategic denial, situates it vis-à-vis realist and liberal explanations, and explains the research design: selecting four contemporaneous cases within one region to hold the broader context constant while varying strategic importance. It previews the core findings from each case and outlines the book’s contribution for scholars and practitioners: a framework that explains otherwise puzzling patterns in targeting, burden-sharing, and post-conflict strategy, and that helps anticipate how great powers adjust methods as rival involvement rises.