The idea that democratic states have not fought and are not likely to fight inter-state wars against each other runs counter to the realist and neorealist theoretical traditions that have dominated the field of international politics. Since the mid-1970s, the generation of new data and the development of superior analytical techniques have enabled evaluators of the idea to generate impressive empirical evidence in favor of the democratic peace proposition, which is reinforced by substantial theoretical elaboration. Some critics argue that common interests during the Cold War have been primarily responsible for peace among democracies, but both statistical evidence and intuitive arguments cast doubt on that contention. It has also been argued that transitions to democracy can make states war-prone, but that criticism too has been responded to persuasively. The diverse empirical evidence and developing theoretical bases that support the democratic peace proposition warrant confidence in its validity.