President Trump said the federal government is looking into whether it can legally stop New York City's new pied-à-terre tax, a levy he called a "dangerous political experiment" that will drive wealthy residents out for good.

Trump posted the warning on Truth Social on Tuesday, one day after a Staten Island judge issued a temporary restraining order halting the tax's rollout. The order came in a lawsuit filed by homeowners who said the city botched implementation by misidentifying who should actually pay the surcharge. Mayor Zohran Mamdani's administration immediately appealed, keeping the tax in effect while a higher court reviews the case.

The pied-à-terre tax, the first of its kind in New York State, targets luxury second homes. It applies to one-, two-, and three-family properties valued above $5 million, and to condominium and cooperative units worth $1 million or more when the owner's primary residence is outside New York City. The Mamdani administration projected the tax would generate roughly $500 million a year when it was unveiled in April.

Over 17,000 wrong tax notices fueled the legal challenge

The restraining order did not come out of nowhere. Fox News reported that the city sent more than 17,000 incorrect tax notices to primary residents who were never supposed to fall under the surcharge. That mass mailing turned a policy debate into a kitchen-table crisis for thousands of homeowners who suddenly believed they owed a tax designed for absentee owners of multimillion-dollar properties.

FOX Business' Cheryl Casone described the judge's ruling as "a massive win for local homeowners." For the Mamdani administration, it was an embarrassment, a rollout error that handed opponents the strongest possible argument that City Hall was not ready to administer its own signature tax.

A judge blocking the tax rollout marked one of the sharpest judicial rebukes Mamdani has faced since taking office.

Trump frames the tax as economic self-destruction

Trump's Truth Social post laid out a blunt economic argument. He said the revenue the city hopes to collect pales next to the tax dollars it will lose when high-income residents leave permanently. USA TODAY reported that Trump has made this case on "numerous occasions," repeatedly warning that Mamdani's policies target wealthier residents and will push them out.

In Tuesday's post, Trump wrote:

"The NYC Pied-a-Terre Tax is costing New York City and State a fortune in that the money, eventually to be gotten, is very little compared to to the TAXES PAID by the tens of thousands of people who are fleeing the City, never to return."

He followed that with a direct statement about federal involvement:

"I am looking to see if the Federal Government has any legal right to avert this disaster, before it is too late, for the millions of people who cherish New York and want to see it thrive, as opposed to becoming a filthy, crime ridden, decrepit place of mockery and scorn."

Trump also linked the pied-à-terre tax to New York's congestion pricing program, calling the combined burden a path to financial and social ruin. He described the situation as "pure Amateur Hour" and said it was difficult, as president, "to sit back and watch it happen, especially to a place I once loved."

The Washington Examiner reported that Trump specifically cited wealthy residents fleeing to states like Florida and Texas, low-tax destinations that have absorbed a steady stream of New York transplants in recent years.

Mamdani's broader tax agenda draws fire from multiple directions

The pied-à-terre tax is only one piece of Mamdani's fiscal strategy. Just The News reported that the mayor is pushing a $127 billion city budget that includes a 2 percent tax hike on millionaires and a combined corporate tax rate exceeding 22 percent, which would be the highest in the nation.

At a Las Vegas event, Trump called out Mamdani directly, saying the mayor is "chasing people out and causing a lot of harm to everybody, and everybody's taxes are going through the roof." On social media, Trump added: "The TAX, TAX, TAX Policies are SO WRONG. People are fleeing. They must change their ways, AND FAST."

The Mamdani administration has framed its approach differently. A release from the mayor's office said the pied-à-terre tax "targets ultrawealthy out-of-city residents and global elites who use New York City real estate as a vehicle for wealth storage rather than as homes." That framing positions the levy as a fairness measure, not a wealth-punishing one.

Mamdani has faced sustained criticism over his broader tax-hike campaign, which some analysts have warned could disproportionately burden homeowners who are far from "ultrawealthy."

Neither Mamdani's office nor Governor Kathy Hochul's office immediately responded to USA TODAY's request for comment on Trump's statements. But the New York Post reported that Hochul did eventually push back, defending the tax as a matter of fairness.

Hochul told the Post:

"It's about paying your fair share. Donald Trump ought to focus on all the pain he's causing New Yorkers and knock it off."

That response sidestepped the core question Trump raised: whether the tax will generate less revenue than it costs by accelerating the departure of high-income earners who pay outsize shares of city and state income taxes.

No clear federal legal pathway, yet

For all the force of Trump's rhetoric, the specific legal mechanism the administration might use remains unclear. USA TODAY noted that "it's not immediately clear what legal pathways the administration is looking into." Trump himself framed the inquiry as exploratory, saying he is "looking to see" whether federal authority extends to blocking a municipal tax.

Trump has also threatened to withhold federal funding from New York City, a separate lever that does not require proving the pied-à-terre tax violates federal law. Whether the administration pursues a legal challenge, a funding condition, or both remains an open question.

The mayor's political standing has eroded on other fronts as well. Mamdani was booed off stage at an NYPD event on Staten Island, the same borough where a judge just blocked his tax, underscoring how thin his public support runs outside deep-blue Manhattan.

The state's leftward political shift has been a recurring flashpoint between Trump and New York's Democratic establishment. Trump previously weighed in after far-left candidates toppled establishment Democrats in New York primaries, warning that the party's progressive wing was dragging the state toward policies voters never asked for.

State lawmakers and Hochul approved the pied-à-terre tax before Mamdani's administration rolled it out. The tax is now caught between a trial court that halted it, an appeals court that has not yet ruled, and a president who says the federal government may step in. For homeowners who received one of those 17,000 erroneous tax notices, the legal limbo is not an abstraction, it is a bill they are not sure they owe.

When a city cannot even mail the right tax notices to the right people, maybe the question is not whether the feds should intervene, but why anyone trusts City Hall to run the program at all.