The threat, if carried out, could reach communities across the country, including in areas that have not formally adopted sanctuary policies. Two previous Trump administration attempts to withhold federal money from sanctuary jurisdictions were struck down by courts, and legal challenges to the current administration’s funding actions are already underway in multiple states.

President Donald Trump announced Tuesday that his administration will halt federal payments to sanctuary cities and all states that contain them beginning Feb. 1, expanding a campaign to use financial pressure against jurisdictions that limit cooperation with federal immigration enforcement.

Speaking at the Detroit Economic Club in Michigan, Trump said he would cut off money to any state home to a local government that resists his administration’s immigration policies. He did not specify which funding streams would be affected.

“Starting Feb. 1, we’re not making any payments to sanctuary cities or states having sanctuary cities, because they do everything possible to protect criminals at the expense of American citizens and it breeds fraud and crime and all of the other problems that come,” Trump said. “So we’re not making any payment to anybody that supports sanctuary cities.”

When reporters in Washington asked which funds would be cut, Trump said, “You’ll see. It’ll be significant.”

Courts have blocked similar moves before

Two previous Trump administration efforts to cut federal funding to sanctuary jurisdictions were struck down by courts. In 2017, courts rejected a first-term attempt to cut funding to sanctuary cities. More recently, a California-based federal judge struck down a Trump executive order directing federal officials to withhold money from sanctuary jurisdictions, despite government lawyers arguing the order was too early to challenge because no action had yet been taken and no specific conditions had been laid out.

What counts as a sanctuary jurisdiction

There is no universal definition for sanctuary policies. The terms generally describe jurisdictions that limit their cooperation with Immigration and Customs Enforcement.

The Justice Department published a list of approximately three dozen states, cities, and counties it considers sanctuary jurisdictions. The list is overwhelmingly made up of places governed by Democrats, including the states of California, Connecticut, and New York; cities such as Boston and New York; and counties including Baltimore County, Maryland, and Cook County, Illinois. An earlier, longer version of the list drew pushback from officials who said it was unclear why their jurisdictions had been included.

Other funding battles already underway

The administration has moved to halt funding in several areas in recent weeks, with legal challenges already pending in multiple cases.

The U.S. Department of Agriculture warned states that refused to provide data on recipients of Supplemental Nutrition Assistance Program benefits that they would be docked administrative funds. A court fight over the data request was already underway before that warning was issued, and no money has been stopped yet.

The Department of Health and Human Services said it halted money from five Democratic-led states for daycare subsidies and other aid to low-income families with children over unspecified fraud suspicions. A court put that action on hold.

The Centers for Medicare and Medicaid Services told Minnesota it intends to withhold $515 million every three months from 14 Medicaid programs it deemed high risk, after rejecting a corrective action plan it had demanded over fraud allegations. The $515 million figure represents one-fourth of the federal money for those programs. State officials said Tuesday they are appealing.