Author Biography: David T. Canon is professor of political science at the University of Wisconsin, Madison. His teaching and research interests are in American political institutions, especially Congress. John J. Coleman is professor of political science at the University of Wisconsin, Madison. His teaching and research interests are in the evolution of the American state and the relationship between changes in the political economy of the United States and its party structure. Kenneth R. Mayer is professor of political science at the University of Wisconsin, Madison. His teaching and research interests focus on American political institutions, especially Congress, the Presidency, and defense policy.