Legislator Preferences, Party Desires: The Impact of Party Switching on Legislative Party Positions

Abstract

Democratic politics and political parties go hand in hand. Politicians win elections and hold office as members of parties (Epstein 1967). For their part, political parties organize legislatures and manage the passage of policy (Aldrich 1995; Cox and McCubbins 1993; 2005). Legislators’ political identities are tightly linked to their party affiliations, even where parties are seen as relatively weak vis-à-vis individual politicians. In this light, party switches, particularly when executed by sitting legislators, are curious and perhaps even bizarre. As the first chapter in this book emphasized, there is on one hand the motivational question: why would a legislator decide to change his or her party affiliation during a legislative term? As we also highlighted at the outset, there is on the other hand the practical question of policy consequences: what difference does party switching make? We take up the latter issue here by asking how party switching by sitting legislators affects the preferences of legislative parties.