Using panel data from the US states, we document a robust negative relationship between state-level government corruption and ideological polarization. This finding is sustained when state polarization is instrumented using lagged state neighbor ideology. We argue that polarization enhances political accountability. Consistent with this thesis federal prosecutorial effort falls and case quality increases with polarization. The effect of polarization is dampened when there are other means of monitoring governments in particular strong media coverage of state politics. Tangible anti-corruption measures including the stringency of state ethics' laws and independent commissions for redistricting are also associated with increased state polarization.