Former President Donald Trump, an avowed proponent of tax cuts, is floating the idea of reversing a measure passed during his tenure in the White House that effectively raised taxes for many U.S. homeowners.

In a post Tuesday on Truth Social, Trump suggested he would scrap a $10,000 cap on deducting state and local taxes (SALT) that was passed as part of the 2017 Tax Cuts and Jobs Act — a massive revamp that he has said boosted economic growth. 

Now, in the run-up to the November election, Trump said in the post he would “get SALT back, lower your taxes, and so much more,” although he stopped short of offering details. Trump made the post ahead of a speech he’s giving Wednesday at the Nassau Coliseum on Long Island.

Trump’s new proposal for getting rid of his $10,000 SALT deduction cap comes as the presidential hopeful is pitching several additional tax cuts that would, if enacted, reduce taxes for major groups of voters. He’s also vowed to eliminate taxes on Social Security benefits, a pledge that could get support from the nation’s senior citizens, as well as to end income taxes on tipped workers and on overtime pay, ideas that would help lower- and middle-income Americans. 

Yet Trump’s reversal on the SALT deduction has sparked skepticism from lawmakers as well as economists and policy experts. 

“So … now Trump is against the SALT tax cap which *checks notes* is a key part of the — only — major piece of legislation passed during his administration?” noted Chris Koski, a political science professor at Reed College in Portland, Oregon, on X.

Rep. Tom Suozzi, a Democrat from Nassau, Queens, said in a statement on Wednesday that he is “happy that the former president is saying that he has finally reversed his devastating decision in 2017 to cap the State and Local Tax (SALT) deduction.” He also urged Trump to convince Republican lawmakers to vote to restore the full deduction “if he is truly serious.”

The SALT deduction cap “has been a body blow to my constituents for the past 7 years,” Suozzi added.

Senator Chuck Schumer, a Democrat from New York, wrote on X,”Donald Trump took away your SALT dedications and hurt so many Long Island families. Now, he’s coming to Long Island to pretend he supports SALT. It won’t work.”

Asked for details about Trump’s proposal to restore the SALT writeoff, a spokeswoman for the Trump campaign told CBS MoneyWatch: “While his pro-growth, pro-energy policies will make life affordable again, President Trump is also going to quickly move tax relief for working people and seniors.”

Here’s what to know about the SALT deduction. 

What is the SALT deduction?

The state and local tax deduction allows taxpayers who itemize to deduct property taxes, sales taxes and state or local income taxes from their federal income taxes. Prior to the Tax Cuts and Jobs Act, there was no limit on how much people could deduct through the SALT deduction. 

But the 2017 tax overhaul passed under Trump limited the deduction to $10,000 – a blow to many homeowners in states with high property taxes, many of which are Democratic leaning. At the time of the law’s passage, the Treasury Department estimated that almost 11 million taxpayers in high-tax states like New York and New Jersey would forfeit $323 billion in deductions.

Who benefits from the SALT deduction?

Homeowners with high property taxes, such as people in New York, New Jersey and California, were the biggest beneficiaries of the the full SALT deduction. 

But some experts also noted that the SALT deduction primarily put more money in the pockets of higher-earning Americans. About 80% of the full SALT deduction had helped people earning more than $100,000 a year, according to the Tax Foundation. 

What happened after Trump capped the SALT deduction at $10,000?

The limit has increasingly impacted middle-class homeowners across the U.S. because of rising property taxes and incomes. Some lawmakers have also sought to either repeal or increase the SALT cap, but none of those efforts have borne fruit. 

Earlier this year, some lawmakers sought to double the SALT deduction cap to $20,000 for married couples, with the change retroactive for the 2023 tax year. But that bill was blocked in the House in February.

Won’t the SALT deduction cap expire anyway?

Yes, the SALT deduction cap is a provision that’s due to expire in 2025, as are many other parts of the Tax Cuts and Jobs Act, such as a reduction of the individual tax brackets. But Trump has previously indicated he wants to extend the provisions in his signature tax law.

How much would it cost the U.S. to repeal the SALT deduction cap?

It won’t be cheap, according to the the Committee for a Responsible Federal Budget, a think tank that focuses on budget and policy issues. 

Eliminating the $10,000 deduction limit “would increase the cost of extending the 2017 Tax Cuts and Jobs Act (TCJA) by $1.2 trillion over a decade,” the group estimates, adding that such a measure would be a “costly mistake.”

Extending the TCJA’s tax cuts would increase the nation’s deficit by $3.9 trillion over the next decade, the group estimates. By adding in a expiration or repeal of the SALT deduction cap, that would grow to $5.1 trillion, it added.

“Lawmakers should not extend the TCJA without a plan to – at a minimum – offset the costs of extension, but ideally the plan would raise revenues relative to current law and help put the nation’s debt on a better trajectory,” the group said in a statement.