Quarterly Journal of Political Science > Vol 5 > Issue 2

Primary Elections and Partisan Polarization in the U.S. Congress

Shigeo Hirano, Department of Political Science, Columbia University, USA, sh145@columbia.edu , James M. Snyder Jr., Departments of Political Science and Economics, Massachusetts Institute of Technology and NBER, USA, millett@mit.edu , Stephen Ansolabehere, Department of Government, Harvard University, USA, sda@gov.harvard.edu , John Mark Hansen, Department of Political Science, University of Chicago, USA, jhansen@midway.uchicago.edu
Suggested Citation
Shigeo Hirano, James M. Snyder Jr., Stephen Ansolabehere and John Mark Hansen (2010), "Primary Elections and Partisan Polarization in the U.S. Congress", Quarterly Journal of Political Science: Vol. 5: No. 2, pp 169-191. http://dx.doi.org/10.1561/100.00008052

Publication Date: 11 Aug 2010
© 2010 S. Hirano, J. M. Snyder Jr., S. Ansolabehere and J. M. Hansen
Electoral institutions,  Lawmaking


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In this article:
Polarization and the Introduction of Primaries 
Polarization and Ideological Composition of Primary Voters 
Primary Competition and Senate Polarization 
Roll Call Voting Positions and Electoral Outcomes 


Many observers and scholars argue that primary elections contribute to ideological polarization in U.S. politics. We test this claim using congressional elections and roll call voting behavior. Many of our findings are null. We find little evidence that the introduction of primary elections, the level of primary election turnout, or the threat of primary competition are associated with partisan polarization in congressional roll call voting. We also find little evidence that extreme roll call voting records are positively associated with primary election outcomes. A positive finding is that general election competition exerts pressure toward convergence as extreme roll call voting is negatively correlated with general election outcomes.

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Quarterly Journal of Political Science, Volume 5, Issue 3 10.1561/100.00080521