The importance of citizen trust in government derives from its role in democratic theory. Presumably, the decisions of trusted authorities and institutions are more likely to be accepted as legitimate and worthy of support than are those of distrusted leaders and institutions.

I have long been interested in the question of how cooperation can emerge in a world of egoists without central authority. Over a period of five years, culminating in my book on the Evolution of Cooperation (1984), I published a series of studies that explored the emergence and maintenance of cooperation in the context of the two-person iterated Prisoner's Dilemma (PD). I was well aware that two-person interactions can tell only part of the story of cooperation in societies, so I thought about various ways of building and sustaining cooperation when one person's actions can affect many others. Unfortunately, the most straightforward way to extend the two-person PD game would not sustain cooperation unless something else was added to solve the collective action problem by preventing free riders.

“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.

I frequently tell my graduate students that a good indicator that a piece of work has attained the status of a classic is the extent to which it is cited irrelevantly. Although I have been vaguely conscious in the years since this article was published that it has turned up in a lot of footnotes, I have not followed its career in the literature closely enough to be able to tell whether by this austere criterion it qualifies.

”The Silent Revolution in Europe” was the first presentation of the intergenerational value change hypothesis. It argued that the publics of postindustrial societies are shifting from giving top priority to “Materialist” goals such as economic and physical security to placing increasingly strong emphasis on self-expression and the quality of life. Throughout history, survival has been insecure for most people, forcing them to give top priority to survival needs. But in advanced industrial societies, the economic miracles of the postwar era and the emergence of the welfare state gave rise to conditions under which much of the postwar generation grew up taking survival for granted; they give increasingly high priority to “Postmaterialist” values such as belonging, self-expression, and free choice. Because people's basic values do not change overnight, those who experienced the insecurity of World War I, the Great Depression, and World War II would continue to emphasize Materialist values, but we would expect to find an intergenerational shift toward Postmaterialist values.

This article—one of only two on the “top twenty” list published later than 1986—undertook two tasks. The first was to examine whether the “democratic peace” was a spurious relationship that could be disconfirmed by several possible alternative explanations. The second was to provide a stepping stone—to be revised and improved by others—for converting the democratic peace from a theoretically loose, substantially intuition-driven project into a research program in which theory and empirics reinforced each other.

Bernard Berelson wrote a memoir about Human Behavior: An Inventory of Scientific Findings, a book that brought together 1,003 findings about human behavior with some reasonable supporting evidence. Berelson offered a threefold grand summary of all social science research: (1) Some do, some don't. (2) The differences aren't very great. (3) It's more complicated than that.