Debate rages over whether Americans have become enormously litigious, but little research considers why Americans file cases in the first place or adequately considers rates of litigation over time. This article examines tort filings in ten representative states over a 20-year period and analyzes the impact of social, political, policy, and legal system factors that may account for case filings. We find that filing rates vary substantially over time within individual states, which adds to cautions about claims of general litigiousness. Our analysis also demonstrates that social complexity, opportunities for political participation, and social policy are the most important explanations for variations in filing rates. The tendency of Americans to use the courts to resolve disputes is related to the milieu in which they live and how the political system responds to demands for participation and social support.