Hence we perceive that the clause which declares the supremacy of the laws of the Union, like the one we have just before considered, only declares a truth, which flows immediately and necessarily from the institution of a federal government.
More immediately, taxpayers in high-tax states are rushing to see whether they can seek extra relief ahead of a new cap on the state and local tax deduction that will go into effect on Jan. 1. Taxpayers will get to deduct only up to $10,000 in both property and income or sales taxes going forward, and GOP negotiators specifically banned people from prepaying 2018 income taxes this year for an extra tax break.
The Itemized Deduction Phase Out. The tax changes also brought back the phase out of itemized deductions in 2013. Like the phase out of personal exemptions, this also affects taxpayers whose incomes exceed certain amounts. For these taxpayers, their deductions for things like mortgage interest, state income and sales tax, and certain other itemized deductions are reduced, but not fully eliminated.