The Limits of Partisan Loyalty

53 Pages Posted: 30 Sep 2018 Last revised: 23 Mar 2019

See all articles by Jonathan Mummolo

Jonathan Mummolo

Princeton University

Erik Peterson

Texas A&M University - Department of Political Science

Sean Westwood

Dartmouth College

Date Written: March 19, 2019


While partisan cues tend to dominate political choice, prior work shows that competing information can mute the effects of partisanship if it relates to salient political issues. But what are the limits of partisan loyalty? How much electoral leeway do co-partisan candidates have to deviate from the party line on important issues? We answer this question using conjoint survey experiments that characterize the role of partisanship relative to issues. We demonstrate a pattern of conditional party loyalty. Partisanship dominates electoral choice when elections center on low-salience issues. But while partisan loyalty is strong, it is finite: voters are more likely than not to vote for the co-partisan candidate until that candidate takes dissonant stances on four or more salient issues. These findings illuminate when and why partisanship fails to dominate political choice. They also suggest that, on many issues, public opinion minimally constrains politicians.

Suggested Citation

Mummolo, Jonathan and Peterson, Erik and Westwood, Sean, The Limits of Partisan Loyalty (March 19, 2019). Available at SSRN: or

Jonathan Mummolo (Contact Author)

Princeton University ( email )

22 Chambers Street
Princeton, NJ 08544-0708
United States

Erik Peterson

Texas A&M University - Department of Political Science ( email )

College Station, TX 77843-4353
United States

Sean Westwood

Dartmouth College ( email )

Department of Government
Hanover, NH 03755
United States
7752293205 (Phone)
7752293205 (Fax)

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