Federal-State Tax Interactions in the United States and Canada

The potential for vertical tax competition is strongest when different levels of government share the same base. Because there is greater sharing of common tax bases in Canada than in the United States, we expect vertical tax competition to be weaker in the United States than in Canada. Econometric analysis of US data supports this hypothesis. Taking account of the deductibility-related endogeneity of federal tax burdens by state, federal income tax burdens have no effect on average state income tax burdens. Introducing distributional considerations into the vertical tax competition model, we do find a significant displacement effect for higher income taxpayers, with higher federal burdens associated with lower state income tax burdens in the highest income quintile. For low-income taxpayers, federal and state tax burdens are complementary.