There is now substantial evidence that defense spending decisions in the United States are influenced by citizen preferences. However, there is little time-series evidence for countries other than the United States. Regression models of citizen responsiveness and opinion representation in the politics of defense spending in five democracies are estimated. Results show that public opinion in all five countries is systematically responsive to recent changes in defense spending, and the form of the responses across countries uniformly resembles the "thermostat" metaphor developed by Wlezien and the more general theory of opinion dynamics developed by Stimson. Findings show also that defense budgeting is representative: public support for defense spending is the most consistently significant influence on defense budgeting change in four countries; thus, a parsimonious theory of comparative policy representation is potentially within reach. The implications of the results for defense spending in the NATO alliance and the European Union are discussed.Keywords: Democratic control; defense spending; public opinion; citizen responsiveness; alliance dynamics A substantial body of scholarship has emerged on the question of democratic control of foreign and defense policy. This literature has produced a surprisingly cumulative set of findings that indicates that citizens are systematically responsive to government policy and that public opinion is an important determinant of subsequent policy change. The evidence indicates, in short, that democratic control of defense policy is a very real phenomenon.However, most of this evidence concerns citizen opinion and representation in the United States. As a result, we have few of the answers that are needed to construct a comparative theory of representation in the domain of defense policy. In particular, we need answers to the following questions: are citizens in all democracies responsive to policy change? Is the form of the response similar? Does public opinion influence pol-icy in all democracies-that is, are all democracies representative?These questions are not merely of theoretical interest. In the United States and Western Europe, defense spending is either already increasing or governments are under pressure to increase it. However, the level and sustainability of public support for increased defense spending remain open questions, especially if deficits loom or civilian spending would be restrained or reduced.Precisely how such pressures will play out is something we do not know on the basis of existing evidence. In this study, we seek to close this gap in our knowledge. We estimate regression models of citizen responsiveness and policy representation in five countries: the United States, Great Britain, France, Germany, and Sweden. The time period covered by our study varies by country, but it generally includes the period from the late 1960s through 1998. 1 Our specific focus is the role of citizen opinion in the politics of defense budgeting, the yearly de...