The promotion of democracy around the world lies at the heart of American post-Cold War foreign policy. As the Clinton administration sees it, democratic institutions bring stable domestic politics and peaceful foreign relations. This important and elegantly argued book shows that, in fact, the opposite is often true: the democratic transition can cause nationalist conflict and aggression. Snyder does not dispute the claim that established democracies are unusually peaceful among themselves, but he finds the initial phases of democratization more problematic. Threatened by change, traditional elites often thwart the move toward popular rule by fanning the flames of ethnic and nationalist conflict. In contrast, countries with strong political institutions and civic culture can better weather such treacherous moments. Marshaling an impressive body of empirical evidence, both historical and contemporary, Snyder tests his hypotheses by first looking at turning points in British, French, and German history. The following survey of the transition in the postcommunist and developing worlds also shows similar connections, concluding that recent nationalist and ethnic violence stems not from resurgent ancient hatreds but from elites struggling to maintain authority. A timely reminder that democracy can produce violence as well as peace.