Tracking trends in American public opinion, this study examines moods of public policy over time. James Stimson looks at shorter term movements as the public approves or disapproves politicians, trusts or distrusts government. His book is distinctive in that it focuses on determining the unobserved true opinion that lies beneath superficial polls. It argues that public opinion is decisive in American politics and identifies the citizens who produce influential change as a relatively small subset of the American electorate.