Estimating Party Influence in Congressional Roll-Call Voting

This article develops and implements a simple procedure to estimate the extent to which party influences roll-call voting in the U.S. Congress. We find strong evidence of party influence in both the House and the Senate, in virtually all congresses over the period 1871-1998. We do not find any large, systematic differences in influence between the House and Senate. Over the post-war period, party influence in the House occurs especially often on key procedural votes-the rule on a bill, motions to cut off debate, and motions to recommit. In terms of substantive issues, party influence appears most frequently on budget resolutions, tax policy, social security, social welfare policy, and the national debt limit, while it is relatively rare on moral and religious issues and civil rights, and entirely absent on issues such as gun control. On some issues, such as agriculture, public works, and nuclear energy, party influence has varied dramatically over the period we study.