Mind the gap: Partisan bias in justifying political violence in the United States

Political polarization in America has intensified beyond mere disagreement to what scholars characterize as sectarianism – a condition where partisan identity fundamentally shapes moral judgments. A key marker of sectarianism is asymmetric moral standards for violence, where aggression against political opponents is considered more justified than identical violence targeting one's own group. Using a survey experiment featuring a realistic political rally scenario, we find compelling evidence in support of such sectarianism: partisan bias in the US extends to evaluations of political violence. By manipulating the partisan affiliations of perpetrators and targets, as well as provocation severity, we find that both Democrats and Republicans exhibit substantial and symmetrical partisan bias. This double standard is particularly pronounced among strong partisans, who are nearly three times more likely to justify violence against the opposition than violence targeting their own party. These results extend sectarianism theory beyond policy preferences to physical violence, suggesting partisan identity now functions as a powerful perceptual filter that can legitimize political aggression when directed at opponents.