Partisan animosity has surged in America over recent decades. This research shows moral conviction, not just partisan identity, drives affective polarization—heightened bias and hostility across party lines—even among politically similar individuals.

* Moral Psychology Insights: Examining how specific moral concerns fuel political division beyond partisanship itself.

* Data Approach: Analyzing responses from two national surveys using novel measures of everyday partisan feelings.

People who moralize politics display stronger bias against opposing parties, regardless of their own party strength or ideology. This suggests a fundamental 'moral divide' shaping American political life and raising important questions about the intersection of ethics and electoral competition.