Political rule (vs. opposition) predicts whether ideological prejudice is stronger in U.S. conservatives or progressives

People see societal groups as less moral, warm, and likable if their ideology is more dissimilar to the ideology of the self (i.e., ideological prejudice). We contribute to the debate on whether ideological prejudice in the U.S. is stronger in conservatives, progressives, or neither. Investigating the American National Election Studies (ANES), we found that between 1972 and 2021, ideological prejudice was stronger in conservatives. However, investigating studies conducted to develop the Agency-Beliefs-Communion (ABC) model, we found that between 2016 and 2021, ideological prejudice was stronger in progressives. We report various analyses of both research programs and two new studies that rule out several explanations for this contradiction. Additional analytic and experimental evidence suggests that political rule (vs. opposition) may explain the robust heterogeneity in asymmetric ideological prejudice. Ideological prejudice shifted toward being stronger in conservatives when the U.S. was governed by Democrats, and toward being stronger in progressives when the U.S. was governed by Republicans.