Collaborative Research on
Legislative Party Switching

Co-Principal Investigators, William B. Heller, Binghamton University, and Carol Mershon, University of Virginia


Democratic politics and political parties go hand in hand. Politicians win elections and hold office as members of parties, and parties organize legislatures. Why, then, would a legislator decide to change party affiliation during a legislative term? How does party switching by sitting legislators affect policy outcomes and the legislative party system? Do mobile politicians represent the leading edge of electoral realignments, or do they forestall stable alignments and hinder party system institutionalization? In examining these and related questions, this research project approaches party switching as an aspect of strategic interaction among legislators. The project investigates a wide range of empirical settings, from Western Europe to the Baltic States, from the United States to Japan, from Russia to Brazil. At the same time, the project integrates formal and empirical approaches to the study of politicians' choices of, and changes in, party affiliation.

Heller and Mershon organized the Research Work Group on Legislative Party Switching (also known as the Party-Switching Research Group, or PSRG) in order to impose some coherence on a new, growing, dynamic, but thus-far chaotic avenue of legislative research. Party switching in legislatures brings to the fore fundamental questions of representation, party organization, and policy making. By bringing together twelve prominent political scientists at different stages of their careers, the PSRG is well equipped both to illuminate the potential of party switching research and to provide a foundation for other scholars interested in the issue. The quality of its members and the breadth of their research mean that the PSRG's work will speak to and become an important referent for a wide range of social scientists.

This website offers an overview of the work of the PSRG. At the Members link, for instance, the names and affiliations of group members are listed, along with a sketch of research that each member is conducting for the project. Click on Events to see a summary of recent and upcoming scholarly gatherings on the topic of party switching, including, of course, the activities of the PSRG itself. The most important recent activity of the PSRG was its first conference, held in Dublin in July 2004. Papers delivered at that conference will soon be available under the Papers link. By clicking on Resources, you can find an extensive bibliography on party switching, along with data sets that members of the PSRG have used in their research.

Heller and Mershon recognize support from the National Science Foundation for this research ("Collaborative Research on Legislative Party Switching: Integrating Theoretical and Comparative Empirical Analyses," NSF SES-0339877 and SES-0339920).