Earlier quoted context omitted.
And why not? I don't see any fundamental reason why your local taxes should be deductible for federal tax purposes.
Because you don't actually have that money. Suppose that the state and the federal government each had a 55% tax rate. Then you would make $1 and owe $1.10. You would owe more in taxes than you make, so you would quit your job. Of course, there is a simple way for the states to fix this -- move the taxes to the business side. Instead of having state income tax, have payroll tax paid by the employer. Then the employer…
Assume for now that we accept the federal government is entitled to raise money for its programs by taxing people's incomes (yes, some people might disagree, but that's a different discussion). Why should a state be allowed to reduce the federal government's take, and therefore shift the burden of paying for federal services to other states, by choosing to increase its own local tax?