By bringing together two bodies of literature - the presidency and political parties - this book makes two important contributions. First, it addresses the gap between presidential public actions and the perceived limited effect they have on public opinion. By examining the short-term effect of speeches of presidents on the entire public, the long-term effect of the speeches on their partisans, and on the reputations of their parties for handling policy, the book shows that presidents are effective leaders of public opinion. Second, the book adds to the scholarly interest in how political parties are viewed by the electorate in terms of policy substance. It suggests that Americans possess coherent reputations of the parties for handling policy challenges, and that these reputations contribute to the party identifications of Americans. The effect of presidents on the reputations and, in turn, party attachments position them as leaders of the party system.