<p>Leading accounts of contemporary democratic decline emphasize the role of polarization in enabling incumbent governments to dismantle democracy from within. This study offers a fuller portrait of this relationship, illustrating how incumbent attacks on democracy themselves produce polarization. We theorize a micro-level link between democratic backsliding events, elite opinion formation, and voter polarization to explain how incumbent efforts to subvert democracy increase negative feelings among citizens towards opposing partisans, thereby boosting polarization. Using survey experiments, survey data from electoral democracies, and expert-coded global macro-data, we find support for our argument. Regardless of how polarized society is prior, we demonstrate that incumbent actions that degrade democracy worsen polarization, an effect that is amplified when party elites endorse (rather than condemn) the leader’s behavior. The central message to emerge is that polarization is endogenous to democratic backsliding.</p>