Election Outcomes and Affective Polarization in the United States

Do election outcomes exacerbate affective polarization? While polarization often rises during campaigns and correlates with democratic backsliding, isolating the effect of winning or losing has proven difficult because of the need for a pre-election baseline and to generalize across multiple elections. In this study, we leverage pre- and post-election questions about partisan affect in the American National Election Study between 1996 and 2024. Our first analysis studies how respondents’ attitudes changed based on their party’s success in its bid for the White House. Our second analysis extends this to hundreds more races, applying a regression discontinuity design to attitudes after close subnational election results. Both analyses support the conclusion that the losing side drives the post-election gap in polarization, and that they do so by feeling less warmly toward their own party. In the United States, political loss may erode in-group attachment more than it fuels out-group hostility.