Why do democracies win wars? This is a critical question in the study of international relations, as a traditional view--expressed most famously by Alexis de Tocqueville--has been that democracies are inferior in crafting foreign policy and fighting wars. In Democracies at War, the first major study of its kind, Dan Reiter and Allan Stam come to a very different conclusion. Democracies tend to win the wars they fight--specifically, about...