Despite the current rhetoric of Western leaders, democracies are great and frequent war-makers and interventionists. This fact stands in a strange contrast to the liberal self-image of democracies being particularly peaceful. Addressing this contrast, the book turns the 'democratic peace' theme on its head: rather than investigating the reasons for the supposed pacifism of democracies, it looks for the causes of their militancy. In order to solve this puzzle, the authors transcend the disciplinary boundaries of International Relations and draw on political theory, political philosophy and sociology.