“Liberalism and World Politics” had an impact because it is short and (by my standards) well written. I am sure its brevity has attracted anthologists. The more substantial reasons for its impact seem to me to be the following five: First, the article addressed an important anomaly. Traditional theories of democratic foreign policy said that democracies would inherently be peaceful. The mainstream of the literature on war and peace refuted that claim. A group of carefully done empirical studies suggested that democracies were peaceful, but only with one another. This article resolved the anomaly by outlining the logic of how states that were both liberal and representative would maintain peace with one another, but not reliably with nonliberal, nonrepresentative states. It argued that although states throughout history have gone to war with one another to advance both their rational national and nonnational governmental interests, liberal democratic peoples have, by and large, respected one another's sovereignty and security.