Party Loyalty and Electoral Competitiveness in the U.S. Senate

Abstract

As the 2010 midterm election approaches, U.S. senators running for reelection encounter conflicting partisan and electoral pressures. Those facing competitive general elections appeal to swing voters by distancing themselves from their party. Meanwhile, senators have strong incentives to demonstrate their party loyalty to colleagues, party leaders, and their party’s electoral base. When senators vote, they must balance these partisan and electoral considerations. I hypothesize that senators facing competitive elections will be less likely to vote with their party than other senators. This project examines the link between senators’ voting records and the competitiveness of Senate elections from 1996 to 2008. Using elections data and vote studies from Congressional Quarterly, I compare senators facing competitive elections with senators defending safe seats. In addition, I analyze changes in senators’ voting patterns over their six-year terms. My results help explain partisan behavior in the U.S. Senate and provide insight into the upcoming election.