The Trump administration’s Department of Justice has filed a series of federal lawsuits targeting state and local “sanctuary” policies that limit the use of state and local resources for federal civil immigration enforcement.
In each lawsuit, the DOJ argues that these laws and ordinances unlawfully obstruct federal immigration enforcement and violate the Supremacy Clause of the Constitution by discriminating against or directly regulating federal officials. The challenged policies vary in scope, but all reflect local efforts to preserve community trust, ensure the functioning of courts and justice systems, and prevent the entanglement of local agencies in federal civil immigration operations. Examples include rules defining when officials may honor ICE detainer requests, share personal information with federal agents, or permit federal agents access to state or city facilities.
State and local governments, joined by community organizations, law enforcement leaders, and former judges, have defended these policies as lawful exercises of state and municipal authority protected by the 10th Amendment, which reserves all powers not entrusted to the federal government to state and local governments instead. They emphasize that Congress has never mandated local participation in civil immigration enforcement and that federal law preserves significant discretion for state and local officials to set policing and publicsafety priorities.
On November 25, 2025, the Brennan Center, along with co-counsel Anderson & Kreiger LLP, filed a friend-of-the-court brief on behalf of former law enforcement officials in support of the City of Boston’s motion to dismiss the DOJ’s lawsuit.
On December 9, 2025, the Brennan Center filed a second friend-of-the-court brief on behalf of former law enforcement officials in support of New York City’s motion to dismiss the DOJ’s lawsuit.
Both briefs are from law enforcement professionals with decades of leadership experience in policing, prosecution, and corrections. They argue that policies limiting local law enforcement’s participation in federal immigration work do not harm public safety. On the contrary, drawing clear boundaries between local law enforcement and ICE helps police and prosecutors communicate clearly about their public safety mission and retain community trust. The briefs emphasize that these policies improve crime reporting, facilitate community cooperation with police and prosecutors, and protect public safety without undermining federal immigration objectives.
On May 28, 2026, the district court granted Boston’s motion to dismiss the lawsuit without prejudice, finding that the federal government had failed to establish standing to sue, a requirement for federal courts to hear a case under Article III of the Constitution. Among other things, standing requires plaintiffs to establish an injury that is redressable by a federal court. But, the court concluded, controlling state law separately prevented Boston officials from detaining people merely to facilitate transfer to ICE custody — something beyond the court’s power to alter. Similarly, because there was no conflict between city and federal laws on the sharing of information between ICE and city officials, there was no injury to redress.
Documents (United States v. City of Boston)
- DOJ complaint
- Motion to dismiss
- Memorandum of law
- Opposition to motion to dismiss
- Reply in support of motion to dismiss
- Memorandum — Decision and order dismissing case
Documents (United States v. City of New York)
- DOJ complaint
- Motion to dismiss
- Memorandum of law
- Opposition to motion to dismiss
- Reply in support of motion to dismiss
Amicus Briefs