Sanctuary Cities

What Is a Sanctuary City

A sanctuary city is a state, county, or city that limits how much its own police and agencies help with federal immigration enforcement. Most often that means declining to hold someone in jail past their release date just because ICE asked, or limiting what local staff share with federal agents. It protects local trust in police, and it keeps local officers focused on local crime rather than acting as an arm of immigration enforcement.

There is no single legal definition of a sanctuary city. The label covers a wide range of policies, from a sheriff who simply will not hold inmates for ICE without a warrant to a state law barring agencies from sharing certain data. That is why different counts of “how many” sanctuary jurisdictions exist can vary so widely.

What Sanctuary Policies Do and Do Not Do

The most common myth is that a sanctuary city is a place where immigration law stops at the city line. It is not. Federal agents can and do operate in every jurisdiction in the country, sanctuary or not. The policy only governs what the local government itself will do.

Question	What a sanctuary policy does	The common myth
Can ICE operate there	Yes. Federal agents enforce immigration law in every jurisdiction.	That ICE is barred or kept out of the city
Are immigrants immune from federal law	No. Federal law applies everywhere; no one is shielded from it.	That immigrants cannot be arrested or removed there
Must local police honor ICE detainers	No. Detainers are requests, so localities can decline them.	That ignoring a detainer breaks federal law
Who pays if a locality wrongly detains someone	The locality, which can be sued for a Fourth Amendment violation.	That holding for ICE carries no legal risk

The last row is the practical reason many sheriffs adopt these policies. Courts have held that jailing someone past their release on a detainer alone, with no judicial warrant, can violate the Fourth Amendment and leave the county on the hook for damages. Declining detainers is often the cautious legal choice, not a political one.

The Tenth Amendment Basis

The legal foundation for sanctuary policies is the Tenth Amendment and a rule the Supreme Court calls anti-commandeering. The federal government cannot force state or local officers to carry out a federal program. It can ask for help, and it can run its own enforcement, but it cannot draft local police into the job.

The Court set this rule in Printz v. United States in 1997, with Justice Antonin Scalia writing for the majority. The case struck down a federal law that ordered local sheriffs to run background checks for gun purchases. The same principle means Washington cannot order a city’s police to enforce immigration law.

This is why an ICE detainer is a request rather than a command. ICE can ask a jail to hold someone for up to 48 extra hours so agents can pick them up, but the jail is free to say no. A locality that holds someone anyway, without a judge’s warrant, takes on the legal risk itself.

The principle is not just history. In June 2026, a federal judge quashed the Justice Department’s subpoenas of Minnesota Gov. Tim Walz and other officials, ruling that Washington cannot coerce state officials into doing federal immigration enforcement. Declining to help is a right the Constitution protects, not a crime.

The Funding Fight

The current fight is over money, and it has moved through the courts since early 2025. A January 20, 2025 executive order directed the Justice Department and Homeland Security to identify sanctuary jurisdictions and withhold federal funding from them. By 2026 the administration was threatening to cut funding not just to sanctuary cities but to their entire states.

The funding arc runs from a 1997 ruling that limits federal power, through the 2025 order and a botched list, to the court blocks that followed.

1. 1997 Printz sets the anti-commandeering rule The Supreme Court holds Washington cannot force local police to enforce federal law.
2. Jan 2025 Executive order targets sanctuary funding An order directs agencies to list sanctuary jurisdictions and withhold federal money.
3. May 2025 DHS posts then pulls a 500-plus list A broad list of jurisdictions comes down within days over accuracy complaints.
4. Aug 2025 A federal judge blocks the funding cuts The court bars the administration from withholding funds over sanctuary status.
5. 2026 Administration threatens to defund whole states The funding threat expands from cities to their entire states.

Sources: Supreme Court; Department of Justice; NPR.

The sanctuary funding fight, 1997 to 2026: 1997 — Printz sets the anti-commandeering rule (The Supreme Court holds Washington cannot force local police to enforce federal law.). Jan 2025 — Executive order targets sanctuary funding (An order directs agencies to list sanctuary jurisdictions and withhold federal money.). May 2025 — DHS posts then pulls a 500-plus list (A broad list of jurisdictions comes down within days over accuracy complaints.). Aug 2025 — A federal judge blocks the funding cuts (The court bars the administration from withholding funds over sanctuary status.). 2026 — Administration threatens to defund whole states (The funding threat expands from cities to their entire states.).

1997: In Printz v. United States, the Court ruled that the federal government cannot command state and local officials to administer a federal regulatory program, the rule that protects sanctuary policies today.

January 2025: A January 20, 2025 executive order directed the Justice Department and DHS to publish a list of sanctuary jurisdictions and to identify federal funds that could be withheld from them.

May 2025: DHS published a list of more than 500 jurisdictions in late May 2025 and pulled it within days after local officials disputed its accuracy. The Justice Department later issued a narrower official list of about 35.

August 2025: On August 23, 2025, a federal judge blocked the administration from cutting funding to sanctuary cities, pointing to South Dakota v. Dole, the 1987 ruling that bars Congress from attaching coercive conditions to federal money.

2026: The administration escalated, threatening to cut funding to sanctuary cities and the states that contain them, which courts have continued to block.

Sanctuary Cities by the Numbers

The numbers cut against the fear-based case. The official list is small, the legal ground is decades old, the courts have sided with localities, and the crime research does not show the harm the policies are accused of causing.

The crime evidence comes from several independent analyses. A Stanford study, a review of more than 2,000 counties, and a New York City study each found no increase in crime tied to sanctuary policies, and several found lower crime. Researchers point to trust policing, where people are willing to report crimes and act as witnesses because they do not fear that contact with local police will trigger deportation. One finding is that some undocumented immigrants are roughly 70% less likely to report a crime when they fear immigration consequences, which makes everyone less safe.

Why It Matters

Sanctuary policies decide whether your local police spend their time on local crime or on federal immigration work. When a city pulls its officers out of immigration enforcement, victims and witnesses are more willing to come forward, and the police keep the community trust they need to solve cases. That is the public-safety argument, and the crime data backs it.

The funding fight matters because it tests whether Washington can punish a city for a local policy choice the Constitution protects. If the federal government could cut off unrelated grants until a city agreed to do federal immigration work, the Tenth Amendment limit would mean little. The courts have so far said it cannot, which is why the cases keep going the localities’ way.

The Honest Disagreement

Serious people disagree about sanctuary policies, and the disagreement is real. We lay out both cases and let you weigh them.

The case for sanctuary policies rests on local control and community trust. Supporters, including the American Immigration Council and the Vera Institute, argue that the Tenth Amendment bars Washington from drafting local police, that honoring detainers without a warrant invites Fourth Amendment lawsuits, and that crime data shows no harm and often a benefit when local police stay out of immigration work.

The case against rests on federal supremacy and public safety. The administration and its supporters argue that immigration is federal law, that local cooperation makes enforcement more effective, and that declining detainers can release people who go on to commit crimes, pointing to individual cases as evidence.

At bottom this is a federalism debate about who controls local police, not a question of whether federal immigration law exists. The courts have largely upheld the right of localities not to be commandeered and have struck down the threats to cut their funding. We do not declare a winner on the policy question.

Frequently asked questions

Can ICE still arrest people in a sanctuary city? Yes. Federal agents enforce immigration law everywhere, including sanctuary jurisdictions. A sanctuary policy only limits what the local government does to help, such as holding someone in jail for ICE without a warrant.

Do sanctuary cities break federal law? No. There is no federal law requiring local police to enforce immigration law, and the Supreme Court has held that Washington cannot force them to. Declining a detainer is a lawful choice, not defiance of federal law.

Do sanctuary cities have more crime? Independent studies, including a Stanford analysis and a review of more than 2,000 counties, found no increase in crime from sanctuary policies, and several found lower crime. Researchers tie this to people being more willing to report crimes.

Can the president cut their funding? So far, no. Courts have repeatedly blocked the administration from withholding federal funds over sanctuary status, citing the rule that Congress cannot attach coercive conditions to unrelated money.

What you can do

1. Tell your members of Congress to reject funding threats against localities. Cutting a city’s unrelated federal grants to force it into immigration work is the coercion courts keep blocking. Ask each of your representatives, on the record, to oppose any bill that conditions general federal funding on local immigration cooperation. Use the letter and call script below.

2. Defend community-trust policing in your own city. Tell your mayor, city council, and sheriff that you want local police focused on local crime, not acting as immigration agents. Trust policing only works when people are not afraid to call 911.

3. Ask your sheriff about detainer practice. Sheriffs decide whether the county holds people for ICE without a judicial warrant. Ask yours, in writing or at a public meeting, what the policy is and whether it exposes county taxpayers to Fourth Amendment lawsuits.

4. Learn the related fights. Read our DACA explainer on the program protecting people brought here as children, and our Posse Comitatus Act explainer on the limits of using the military for domestic enforcement.

5. Write your representative using the letter below and ask for a clear, on-the-record commitment to oppose federal funding threats over local immigration policy.