Conclusion

This conclusion synthesizes the book’s findings on major-power intervention in civil wars across Syria, Libya, Yemen, and Sudan. It argues that great powers intervene along a spectrum that reflects perceived strategic value: high-stakes conflicts trigger direct military involvement, medium-stakes cases generate indirect and enabling support, and low-stakes arenas prompt minimal, largely diplomatic engagement. Across cases, a consistent motive emerges; strategic denial acting primarily to prevent a rival from consolidating influence rather than to expand one’s own. Defensive realist logic best explains Russia’s behavior, especially where long-standing access and status were threatened, while offensive realist incentives help account for the U.S.’s readiness to exploit windows of opportunity at acceptable cost. The chapter reviews how this lens clarifies otherwise puzzling choices in targeting, burden sharing, and post-conflict strategies, and it discusses policy implications for anticipating escalation, managing proxy risks, and using regional institutions to limit great-power competition. Recognizing denial as a primary objective, and intervention as a graded response to stakes, provides a more accurate framework for understanding when, how, and why major powers choose to intervene, or hold back.