Partisanship as a Social Identity: Implications for Polarization

The claim that partisanship has developed into a social identity is one of the dominant explanations for the current rising levels of affective polarization among the U.S. electorate. We provide evidence that partisanship functions as a social identity, but that the salience of partisan identity—in and of itself—does not account for increased affective polarization. Using a two-wave panel survey capturing natural variation in the salience of politics, we find that partisanship contributes more to individuals’ self-concept in times of heightened political salience. We also show that partisans can be detached from their Democratic or Republican identity by having them focus on individuating characteristics (by way of a self-affirmation treatment). However, we find only limited evidence that when partisan social identity is made less salient, either by way of natural variation in political context or through a self-affirmation treatment, partisans are any less inclined to express in-party favoritism and out-party hostility. Taken together, our evidence shows that partisanship does operate as an important social identity, but that affective polarization is likely attributable to more than the classic in-group versus out-group distinction.