Civil wars run deep through our historical narratives, shaping the political and social consciousness of people in developed countries around the world: Japan, Russia, Spain, China, Mexico, and the United States, to mention only a few. But intrastate conflicts are not merely features of the past. Today, there are some thirty active civil wars, ranging from Afghanistan and Syria to the Democratic Republic of the Congo, with the average duration of conflict increasing over the past twenty years.1 Most civil wars have broken out in states with limited material capabilities. Major powers have sometimes, but not always, become involved in these conflicts, something that happened less often in the past. Many of these contemporary civil wars are the sources of immense human suffering and regional insecurity, some giving rise to mass exodus and uncontrollable refugee spillover.
Nevertheless, foreign-policy practitioners and scholars alike disagree on the actual risks that high levels of intrastate violence pose to major powers and global stability. They also disagree about the extent to which external powers can influence the trajectories of these conflicts, or improve governance in areas that have been afflicted by civil war. Worldviews matter. Realists generally focus on threats associated with interstate rivalries, while liberal internationalists place more emphasis on the risks created by downstream effects and the erosion of norms that underpin the order they seek to maintain.2 Of course, for all, contingency and the particulars also matter. . . .