It is double taxation, and that was the whole original justification for the deduction, which started in 1862, predates that even further, and even the founding fathers discussed it.
Secondly, let's dispense with this damned notion that the SALT deduction is somehow the high tax states benefiting at the expense of the low tax states, it is precisely the opposite. High tax states raise money and take better care of their citizens, and so their citizens consume less federal dollars per capita in need. In other words, state spending lowers the burden of the federal government having to pick up the slack. Isn't this the conservative dream? States rights? Spending decisions on social programs being done at the state level, laboratories of democracy and all that?
The low tax states, primarily RED STATES, do not spend sufficiently on their populations and as a result, are a larger burden on the federal government, requiring more subsidy. It is the low state states that are raising the cost of government for everyone else and it's quite ludicrous to claim states like CA and NY are being subsidized by this.
Most high tax blue states give more money to the federal government than they receive, and most of the low tax red states are a net federal burden.
So not only do California and New York already subsidize and pay for benefits that these low tax states aren't providing for their citizens, in addition to taking care of their own residents, their citizens now have to pay for egregious tax cuts and have a further burden thrust on them.
If you think the SALT deduction is California and New York benefiting at the expense of the red states, how about we impose a new rule that says your state cannot receive more federal dollars than it pays to the treasury,except in natural disasters and emergencies. Then let's see how long your low tax status lasts. Only a few of the low tax red states are net contributors.
The position that local governments shouldn't raise taxes to pay for their own programs is a deliberate attack on the whole concept of local control, states rights, and a smaller federal government. If states are not handling their people's needs, it just means the Federal government will be bigger and more invasive.
My question is, why do I have to pay for and subsidize the lack of government in these low tax, freeloader states? I mean, this is a rhetorical question, these are my fellow American citizens and the rich states should help the poor ones. But do you see how this faux GOP messaging about blue states could be turned around? I don't mind that my state is a net giver, but I'm really angry about claims we're takers and need to pay more. If you need more, maybe we'll pay more, but don't try an ideological wealth transfer from blue states to red states to appease your voting block and then turn around and lie about the reasons for these cuts. If you want to close my SALT deduction to pay for much needed middle class relief, infrastructure, or services, I'm all for it. But eliminate it so you can give the top 1% an enormous marginal tax break, or give a handful of ultrawealthy dynastic families an estate tax break? Hell no.
Secondly, the GOP tax plan isn't about you. They passed permanent budget busting tax cuts for corporations, for wealthy estates, didn't touch the carried interest loophole, and gave marginal tax cuts that will expire for you in a few years. They tried to eliminate deductability of tuition expenses for kids, for teachers, for medical expenses, and a host of other mostly middle class deductions, while adding loopholes for wealthy prep-school tuition. They hit the endowments of private colleges like Stanford, Harvard, etc with an endowment tax, while trying to exclude religious conservative degree mills. This think is a damn ideological sham with blatant attempts to punish democratically leaning states and institutions that aren't even veiled, and sold as what every knows is a sham, with the new budget deficits providing the justification needed to gut entitlements.
I expect I'll be voted down, but my state has high taxes because we like having a top university system, we like taking care of our people, and we like cleaning up our environment. Maybe these other states don't, that's for their voters to decide, it is the right of Californians to spend more of their own money to take of their people instead of asking the Feds to do it.