From the Summary: "Under current law, taxpayers who itemize can deduct state and local real estate taxes, personal property taxes, and income taxes from federal income when calculating taxable income. In addition, a temporary deduction for sales taxes in lieu of income taxes is available, though it expires December 31, 2011. The federal deduction for state and local taxes results in the federal government paying part of these taxes through lower federal tax collections. Theory would suggest that taxpayers are willing to accept higher state and local tax rates and greater state and local public spending because of lower federal income taxes arising from the deduction. In addition, there is some evidence that state and local governments rely more on these deductible taxes than on nondeductible taxes and fees for services. Repealing the deductibility of state and local taxes would affect state and local government fiscal decisions, albeit indirectly. Generally, state and local public spending would decline, although the magnitude of the decline is uncertain. And, repealing the deduction for state and local taxes would shift the federal tax burden away from low-tax states to high-tax states. Maintaining the current deductibility would continue the indirect federal subsidy for state/local spending."
CRS Report for Congress, RL32781