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 eighty percent of the time. Complementing their wide-ranging case-study analysis, the authors apply innovative statistical tests and new hypotheses. In unusually clear prose, they pinpoint two reasons for democracies' success at war. First, as elected leaders understand that losing a war can spell domestic political backlash, democracies start only those wars they are likely to win. Secondly, the emphasis on individuality within democratic societies means that their soldiers fight with greater initiative and superior leadership. Surprisingly, Reiter and Stam find that it is neither economic muscle nor bandwagoning between democratic powers that enables democracies to win wars. They also show that, given societal consent, democracies are willing to initiate wars of empire or genocide. On the whole, they find, democracies' dependence on public consent makes for more, rather than less, effective foreign policy. Taking a fresh approach to a question that has long merited such a study, this book yields crucial insights on security policy, the causes of war, and the interplay between domestic politics and international relations.