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.
If Trump does end up signing the bill before the end of the year, the bill will go into effect on January 1, 2018. But regular Americans won't feel the effects of tax reform until spring 2019, when they file taxes for 2018. That means people won't see changes to their tax returns until after the 2018 mid-term elections.