President Donald Trump is fighting back against states that refuse to aid his immigration agenda after a wave of court losses, with a series of new lawsuits that tee up untested legal questions about the power of state and federal governments.
The Justice Department last week filed four lawsuits against states that have refused to approve unmarked license plates for the cars of federal immigration agents.
Federal judges have mostly ruled against Trump’s campaign to force states and cities to cooperate with the president’s mass deportation efforts. Most recently, a federal judge rejected a Trump challenge to a Boston city ordinance that bars local law enforcement from providing certain immigrant information and other types of assistance to Immigration and Customs Enforcement agents.
That decision was at least the fourth ruling dismissing a case brought in Trump’s second term against Democratic-led cities or states, for policies that limit what cooperation is given to federal agents in immigration enforcement
The Trump administration is running into the same legal obstacles with the cases that it did in his first term, yet is pressing on, including in appeals.
“I think the administrative feels, politically, that this is a winning issue,” said Harry Sandick, an attorney who was involved in sanctuary city legal fights against Trump during his first term. “This is an administration that is willing to lose in court, as they have done repeatedly, if they believe there is a political benefit for pressing a particular rule or policy.”
Acting Attorney General Todd Blanche, in an interview with Sean Hannity posted Tuesday, blamed the federal district judges who were first to hear the cases brought by Trump against the policies.
The “challenge,” Blanche said, “with these sanctuary city lawsuits, is that we have to file them in the sanctuary city, where the bench is terrible – for the most part – on these issues.”
Though Blanche expressed confidence the Supreme Court would eventually agree with Trump, the high court declined to take up a major case against California’s sanctuary laws that his administration lost during his first term.
However, more novel legal questions are emerging from how Democratic officials are trying to erect new types of hurdles to the president’s immigration crackdown. Disputes over mask bans for federal agents and the denials of license plates could be more favorable legal ground for Trump, who has already secured a significant win this spring against a state anti-masking law for ICE officials.
“Some sanctuary policies are, ‘Hey, we’re not going to help the feds, but we’re not going to interfere with how the feds are going to do their job,’” said Matt Crapo, director of litigation for Federation of Immigration Reform, which supports stricter immigration laws and has backed the administration in some of the current cases. “And then the newer, more recent cases are, states are actually trying to interfere or tell the feds how to do their job.”
When Trump returned to the White House in 2025, his administration picked up where it left off in its largely unsuccessful anti-sanctuary crusade in court.
A February 2025 lawsuit against Chicago and Illinois was the first of at least nine legal challenges brought by the second Trump administration targeting more than a dozen states or local jurisdictions
That litigation largely deals with prohibitions blocking state or local officials from sharing certain information with the feds – including dates of release for undocumented immigrants who have been arrested or detained by local authorities.
Other challenged policies instruct local authorities not to honor detainer agreements, requests from the feds that people in the custody of local authorities remain in detention after their release date so they can be picked up for immigration proceedings. Some also include blanket bans on expending resources to assist in civil immigration enforcement.
“Sanctuary City laws and policies are designed to deliberately impede federal immigration officers’ ability to carry out their responsibilities in those jurisdictions,” the Justice Department said in a June 2025 lawsuit against Los Angeles, which a judge is expected to rule on in the coming weeks.
About half of those cases are still pending, but the district courts that have issued rulings have sided with the cities and states, handing DOJ defeats in Illinois, New York, Colorado and now Boston. The administration has been appealing those rulings.
Some of the decisions have turned on the anticommandeering doctrine, which says the US government cannot force states to carry out its enforcement of federal regimes, but courts have also found at times no actual conflict between federal law and the local policies.
“The administration is likely to lose in areas where they’re trying to force the states to affirmatively do something that Congress does not require the states to do,” said Richard Painter, a University of Minnesota Law School professor who served in President George W. Bush’s White House Counsel’s Office.
During the first Trump administration, the 9th US Circuit Court of Appeals relied on similar logic to side with California in the case Trump unsuccessfully tried to convince the Supreme Court to take.
Trump’s efforts to pressure sanctuary jurisdictions by withholding federal funding have also been repeatedly defeated in court, but his administration has pressed forward with the tactic.
The Trump administration’s relentless attacks on sanctuary jurisdictions exemplifies a broader strategy of “governing through intimidations and negotiation,” said Anil Kalhan, a Drexel University Kline School of Law professor.
“The fact that there may or may not be legal merits is beside the point,” Kalhan said, comparing the immigration enforcement fights with states to how this administration has also pushed on universities and the legal community.
The legal fight over state cooperation in immigration enforcement is headed to more uncertain territory because of how the battles on the ground escalated in the last year.
“The surge changed everything,” said Rick Su, University of North Carolina School of Law professor specializing in immigration and federalism. Boosted by a massive influx of funding from Congress, the Trump administration flooded cities that had resisted helping in its deportation efforts with federal agents, which in turn prompted states to try new strategies to shield their residents.
States have described their measures – often aimed at bringing more transparency to how immigration agents are carrying out their mission – as necessary for protecting their residents and within the realm of the policing power the Constitution gives the states. The Justice Department, meanwhile, has accused states of making law enforcement officials vulnerable to surveillance and harassment.
Regardless, the new wave of the litigation challenging those measures poses questions not easily answered by existing precedents.
“The sanctuary cities cases currently are very similar to what it was in Trump 1, and I’m not surprised [by the results] there,” Ilya Somin, a George Mason University Antonin Scalia School of Law professor, said. “On some of these other issues, things are more complicated.”
Trump’s arguments against the new laws point to Constitutional prohibitions on states regulating the way federal agents perform their government functions and on laws that discriminate against the federal government.
The administration secured court orders blocking California laws that barred face masks for federal agents in most circumstances, and that required them to wear markers or badges displaying their identification. But it’s unclear whether judges who are reviewing similar laws passed in Connecticut and New Jersey will come down the same way, Su said, as states that have passed laws since the California rulings have adjusted the measures in response.
The terrain is even more muddled around the new lawsuits the Justice Department filed against Massachusetts, Oregon, Washington and Maine for denying certain federal agents the confidential plates.
On the one side is the argument that states are discriminating against the feds. But on the other side, states can claim that the administration is demanding that they take affirmative steps – by issuing the plates – to assist in a federal operation.
“Not to say that any of these other cases will be easy, but I think this actually straddles the two sides,” Su said.