New research examines how electoral reforms influence legislative polarization through three distinct channels. The study employs a decision-theoretic framework with partial incumbent policy persistence and spatial voting to analyze the effects of reform implementation versus removal in state legislatures. Key findings reveal that reforms encouraging ideological moderation produce significantly larger polarization impacts when implemented compared to being removed, due to changes in electoral competition dynamics. Examining both reform implementation decisions by incumbents and subsequent electoral outcomes demonstrates how seemingly moderate policies can shape partisan divisions.