How Do Americans Explain Their Party Identification and Out-Partisan Animosity?

Political scientists often claim that partisanship is explained by nonpolicy factors such as early childhood experiences, parental influence, and group membership. In this paper, we use open-ended survey questions to elicit partisan Americans’ own explanations for their affiliations as well as their attitudes toward the opposite party. Policy, values, and ideology are the most common reasons Americans say they identify as a Democrat or Republican and feel the way they do about members of the other party. The rate at which these reasons are cited far exceeds expectations of published scholars of partisanship. Findings do not vary meaningfully across party, region, gender, race, age, or socioeconomic status.