Mamdani wins: Can Trump legally stop federal funding to New York City?

But as the Democratic Party nominee and the former New York governor battled to become New York City’s next mayor, United States President Donald Trump remained a larger-than-life figure in the shadows, attacking Mamdani as a “communist” and, crucially, threatening to cut funding for the largest urban hub of the US if the 34-year-old won.
Is Mamdani a communist?
Trump and other US Republicans have repeatedly called Mamdani a communist. Mamdani describes himself as a democratic socialist, and when asked if he was a communist during NBC’s Meet the Press in June, he said, “No, I am not.”

A Muslim US citizen originally from Uganda, Mamdani’s campaign has focused on making New York more affordable for residents with rent freezes, free universal childcare and lower public transport costs. However, most describe him as a socialist, not a communist.

In June, PolitiFact also debunked claims that Mamdani is a communist. “Communism involves a centrally planned economy, with no market forces. Prices and quantities are set by a central government authority. There is no democratic political competition, and instead, a single party rules the country. He is not calling for any of this,” Stanford University professor Anna Grzymala-Busse told PolitiFact.

On Monday, even Cuomo said, “Mamdani is not a communist. He’s a socialist. But we don’t need a socialist mayor either.”
How much does NYC actually depend on federal funds?
According to a New York State Comptroller report, which is an analysis of federal funding for New York published in April this year, the city will require $7.4bn in federal funding for the fiscal year 2026.

The report, published on April 28, showed that the federal funding accounts for 6.4 percent of total spending. The remaining funds came from state taxes, fees and other income. State Comptroller Thomas DiNapoli serves as the chief fiscal officer of New York state.

In the fiscal year 2025, the city’s operational budget was $9.7bn, including $1.1bn in pandemic funds.

The report said federal funding largely goes towards the city’s housing and social services agencies. The Temporary Assistance for Needy Families (TANF) was the largest non-pandemic federal fund for fiscal years 2025 and 2026.

What does the law say?
Under the US Constitution, it is Congress, not the president, which has the authority to decide how federal funds are allocated to states.

Article I of Section 8 of the US Constitution states that Congress can collect taxes and decide how money should be spent on national requirements. Additionally, Article I of Section 9 of the US Constitution states: “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law.”

If the president does not execute federal funding decisions made by Congress, that would be considered an unconstitutional act of “impoundment” on the president’s part.
In 1974, the Impoundment Control Act (ICA) was passed after then-President Richard Nixon tried to withhold funds already approved by Congress. The ICA allows the president to withhold funds appropriated by Congress for 45 days, but his decision to withhold funds must then be approved by Congress. So, while the president gets a degree of discretion over federal funding, Congress still makes the final call.

Congress is currently controlled by the Republican Party. Republicans hold 53 seats in the Senate, while Democrats hold 47; Republicans hold 220 seats and Democrats hold 212 in the House of Representatives.