In this wide-ranging study, the authors use 200 years of congressional roll call voting as a framework for an interpretation of important episodes in American political and economic history. By tracing the voting patterns of Congress throughout the country's history, Poole and Rosenthal find that, despite a wide array of issues facing legislators, over 80 percent of a legislator's voting decisions can be attributed to a consistent ideological position ranging from ultraconservatism to ultraliberalism.