This paper examines the distributional and behavioral impacts of ending the deductibility of state and local taxes against the federal individual income tax. I carry out a number of distributional analyses — considering both variation across income and across states — of the subsidy from deductibility as well as the distributional impact of potential partial reforms. I also consider how behavioral responses affect the distributional analysis. Using a large panel of data on state and local governments, I find that deductibility increases reliance on deductible taxes and increases state and local spending out of own-source revenue.