Journal of Political Institutions and Political Economy > Vol 1 > Issue 2

Reducing Legislative Polarization: Top-Two and Open Primaries Are Associated with More Moderate Legislators

Christian R. Grose, Department of Political Science, University of Southern California, USA, cgrose@usc.edu
 
Suggested Citation
Christian R. Grose (2020), "Reducing Legislative Polarization: Top-Two and Open Primaries Are Associated with More Moderate Legislators", Journal of Political Institutions and Political Economy: Vol. 1: No. 2, pp 267-287. http://dx.doi.org/10.1561/113.00000012

Publication Date: 11 Jun 2020
© 2020 C. R. Grose
 
Subjects
Elections: Campaigns,  Elections: Electoral behavior,  Legislatures: Lawmaking,  Legislatures: Legislative processes,  Elections: Voting theory,  Campaigns
 
Keywords
Electoral institutionsopen primarieselection administrationCongressideology
 

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In this article:
Theory: Primary Election Rules Influence Legislator Roll-Call Voting
The Top-Two Open Primary: A Radically Different Way of Administering Primaries
Party Cues for Voters Differ in the Top-Two Primary Compared to Other Systems
Open Primaries and Closed Primaries
Methods and Analysis
Other Independent Variables
Results: The Top-Two Primary Is Associated with Less Extreme Legislators
Are Incumbents Adapting to New Primary Systems or Are New Members Less Extreme?
Conclusions and Implications
References

Abstract

Partisan polarization in Congress is at its highest levels in more than 100 years. Political reformers advocate for changes to electoral institutions in order to reduce legislative ideological extremity, yet political scientists have been surprisingly skeptical that changes to primary nomination systems affect legislator ideology. I theorize that electoral systems shape legislator ideology. The top-two primary — used in just under one-fifth of all U.S. House elections — incentivizes legislators to moderate. Empirically, I rely on exogenous changes in the introduction and withdrawal of the top-two primary due to ballot proposition or in response to court cases, and examine legislator ideological extremity from 2003 to 2018. The top-two primary has reduced ideological extremity among legislators, relative to those elected in closed primary systems. Legislators elected in open primaries also show some evidence of attenuated extremity. This ideological moderation in top-two and open primaries is found among both incumbents and newly elected legislators.

DOI:10.1561/113.00000012

Companion

Journal of Political Institutions and Political Economy, Volume 1, Issue 2 Special issue - Election Administration and Technology
See the other articles that are part of this special issue.