State Political Context and State Legislative Polarization

• In Event: Parties, Institutions, and Polarization in American State Politics

Abstract

The ideological polarization of the Democratic and Republican parties in Congress over the past three decades has been well-documented, and quantitative work has demonstrated that this trend has been mirrored in state legislatures. Estimates of state legislative polarization, however, show considerable variation in the levels and rates of polarization across states, which existing accounts of polarization do not adequately explain. I develop a theory specifying how state electoral rules and party organizational history affect the relative power of policy-oriented activists in the electoral process and consequently the ideological extremism of state legislators. To test this thesis, I collect in-depth data on legislative elections and roll-call voting in a handful of states as well as a nationwide dataset of state election policies over time. Using comparative state case studies and a series of panel regressions, I assess this hypothesis’ usefulness in accounting for differences in polarization across states and compare its explanatory power to other theories of state legislative polarization. This research contributes to understanding the sources of party change in contemporary American politics and to ongoing work examining the relationship between activists and parties.

Author

• Connor Halloran Phillips, Harvard University