It used to be the case that if you lived in a high tax location, if you fully itemized your return, your local taxes were deductible from the income that your federal income taxes then applied to. This was a subsidy from low tax to high tax states and localities.

But because it only makes sense for the richer among us to itemize their returns fully, this State and Local Tax, or SALT, subsidy lessened the impact that government imposes upon richer people. Replacing this tax with a standardized deduction, as President Donald Trump’s reforms did, was thus an improvement in our taxation system.