Can a State Limit Police Cooperation With ICE?

You can feel the tension in the question itself: immigration is federal, policing is local, and the boundaries are not always intuitive. Across the country, states and cities keep testing those boundaries with laws and policies that limit how state and local officers cooperate with federal immigration officials.

So can a state do that?

Often, yes. A state generally cannot regulate federal immigration enforcement itself, but it usually can decide whether its own officers will help carry it out. That distinction is the difference between preemption (federal law displacing conflicting state law) and anti-commandeering (the federal government forcing states to use their personnel to implement a federal program).

The two powers

1) The federal government controls immigration law

Immigration enforcement is rooted in federal authority: Congress writes immigration statutes, federal agencies enforce them, and federal courts interpret them. States cannot create their own deportation systems or set their own national immigration policy. When states try, they tend to collide with federal supremacy.

A key Supreme Court anchor: in Arizona v. United States (2012), the Court struck down major parts of Arizona’s SB 1070 as preempted, emphasizing that immigration enforcement is a field where federal choices can leave little room for states to impose their own parallel enforcement schemes.

2) States control their police

At the same time, the day-to-day machinery of law enforcement is largely state and local. The Constitution does not create local police departments. States do. Counties and cities do. Which means states ordinarily decide what their officers will prioritize, what they will be trained to do, and what they are allowed to spend time doing during a shift.

What “cooperation” means

In practice, “cooperation with ICE” is not one thing. It can include:

• Communication: answering questions, sharing identity information, or confirming custody status.
• Access: allowing federal officers into a jail or holding facility to interview someone.
• Custody transfers: coordinating release timing or physically transferring a person to federal custody.
• Extra detention: holding someone past their release time based on an ICE detainer request.
• Operational help: transport, staffing, database time, or joint task force work.
• Formal partnerships: voluntary agreements like 287(g) programs where local officers take on specified federal immigration functions under federal supervision.

States and localities can adjust some of these levers more easily than others, and some are constrained by federal statutes and by the Fourth Amendment.

One area that regularly draws litigation is information sharing. Federal provisions such as 8 U.S.C. §§ 1373 and 1644 have been invoked in disputes over what states may restrict employees from sharing, especially immigration status information. Other categories like release dates, addresses, or booking and jail records can implicate separate state confidentiality rules, public-records laws, and constitutional questions. The legal landscape varies by jurisdiction and by how a particular state policy is written.

Supremacy Clause basics

The Supremacy Clause (Article VI) makes federal law “the supreme Law of the Land.” When a valid federal law conflicts with a state law, the federal law wins.

That sounds like it should settle everything. But supremacy is not the same thing as a federal right to state assistance.

• Supremacy means states cannot materially interfere with federal enforcement. A state cannot make it illegal for ICE to operate, cannot punish federal officers for doing federal work, and cannot single out federal immigration enforcement for special state-law hurdles that function as direct regulation of federal operations.
• Supremacy does not automatically mean states must help. A state can be required to not interfere while still being allowed to decline to provide personnel, databases, jails, or overtime to make federal enforcement easier.
• Neutral state laws are treated differently. Courts often distinguish between state laws that directly regulate or discriminate against federal functions, and generally applicable state laws (like labor, contracting, or public safety rules) that only incidentally affect federal activity. Outcomes vary, and even generally applicable laws can be preempted if they substantially interfere with a federal program.

Anti-commandeering

The constitutional engine behind most “sanctuary policy” litigation is not immigration law. It is federalism.

The Tenth Amendment reserves to the states (and the people) powers not delegated to the federal government. From that baseline, the Supreme Court has built a doctrine often summarized as anti-commandeering: the federal government cannot require states to use their legislative or executive machinery to administer a federal regulatory program.

The modern cases are the usual trio:

• New York v. United States (1992): Congress cannot force a state legislature to enact or administer a federal program.
• Printz v. United States (1997): Congress cannot conscript state officers to execute federal law.
• Murphy v. NCAA (2018): Congress cannot issue “direct orders” controlling what state legislatures may or may not do simply to implement federal policy.

Translated into the ICE context, the core idea is simple: ICE can enforce federal immigration law, but it generally cannot compel state and local police to act as its workforce.

This limitation applies to Congress and also to federal agencies. A federal agency generally cannot use regulation to accomplish what Congress could not command directly.

What states can restrict

A state can usually set internal rules for its own agencies. In many states, that includes limits like:

• Limits on holding someone longer solely to facilitate a federal immigration pickup, especially when it is based on an ICE detainer request rather than a judicial warrant.
• Limits on arrests for civil immigration violations (unlawful presence is generally a civil matter under federal law, not a state criminal offense).
• Limits on using state resources like staff time, jail space, transport vehicles, or administrative databases for federal immigration purposes, absent state-law authorization or qualifying legal process.
• Limits on access and interviews such as requiring consent, counsel access rules, or a facility policy for where and when interviews happen, so long as the rules are neutral and not crafted to single out federal enforcement.
• Limits on voluntary information sharing beyond what federal law clearly requires, especially where a state is trying to manage confidentiality, privacy, or employee duties. These disputes often focus on whether a policy restricts immigration status information in particular, or instead restricts other categories like release dates or addresses.

These kinds of policies are typically defended as ordinary state control over state officers: a state is choosing what its employees will do on state time.

Concrete example: a policy that says “Our jail will not hold someone past their release time unless ICE presents a judicial warrant” is typically framed as non-cooperation and Fourth Amendment risk management. A policy that says “ICE agents are not allowed to execute a judicial warrant in our facility” starts to look like interference, depending on the legal authority in play and the scope of the warrant.

What states cannot do

There is a line, and it matters.

States cannot use “we are not helping” as a pretext to actively interfere with federal enforcement. Examples that can trigger preemption problems include:

• Penalizing cooperation that federal law affirmatively protects or requires. If Congress validly mandates a narrow form of information sharing, a state cannot forbid it just because the state dislikes the program.
• Directly regulating federal officers or federal operations. For example, a state cannot impose special state-law licensing, permission slips, or punitive rules that target federal agents for doing federal work.
• Interfering when federal officers have lawful authority to act. A state generally cannot physically or legally obstruct federal officers who are acting pursuant to valid legal process (such as a judicial warrant) or lawful consent. But outside those circumstances, federal agents do not have a general right to enter nonpublic areas of state facilities without permission, and the scope of any warrant or order matters.
• Creating a state-law scheme that functions as immigration regulation rather than police administration, such as state penalties keyed directly to immigration status in ways the Supreme Court has treated as stepping into federal territory.

The key difference is between declining to provide state help and placing extra barriers in front of federal enforcement.

Civil vs. criminal

It is true that being unlawfully present is generally civil under federal law. But immigration law also includes criminal offenses, such as illegal reentry, certain document fraud, and some harboring-related crimes. A state’s “no civil immigration enforcement” policy does not change whether federal criminal immigration laws exist, or whether federal officers can enforce them.

Detainers and the Fourth Amendment

Many cooperation fights revolve around ICE “detainers.” Under federal regulations, a detainer is typically a request that a jail hold someone for a limited period after they would otherwise be released, so ICE can assume custody. A detainer is not, by itself, a judicial warrant, even if it is accompanied by administrative immigration documents such as Forms I-200 or I-205, which are not issued by a judge.

Federal regulations also contemplate a maximum request period of up to 48 hours after the time the person would otherwise be released, typically excluding weekends and holidays. Whether a state or county may honor a detainer often turns less on immigration power and more on constitutional criminal procedure.

• If the hold becomes a new seizure without a judicial warrant or other sufficient legal basis, it can raise Fourth Amendment problems.
• If the detainer is treated as optional, a state can say: our officers will not extend custody unless we have a warrant or another legally sufficient basis under state policy.

This is one reason you see states and localities building rules around “warrant requirements.” They are not necessarily asserting control over immigration. They are asserting caution about unlawful detention liability.

Can Congress force cooperation?

Congress has tools, but they are narrower than people assume.

Funding and contracts

The federal government can offer grants tied to certain conditions (within constitutional limits), and it can enter formal agreements with state and local agencies, including structured cooperation programs. If a state wants the money or the contract, it can agree to the terms.

287(g) is voluntary

One prominent cooperation mechanism is the 287(g) program. It is voluntary and typically implemented through a written memorandum of agreement (MOA). It can authorize local officers to perform limited, defined immigration functions under federal supervision, not general immigration policing on whatever terms the locality chooses.

No drafting local police

Anti-commandeering doctrine is designed to stop the federal government from solving a staffing problem by drafting state governments into service. That does not mean every federal condition is invalid. It does mean direct mandates aimed at turning local police into federal immigration agents are constitutionally vulnerable.

One contested corner involves federal information-sharing rules, including 8 U.S.C. § 1373 (and related provisions such as § 1644). Litigation outcomes and legal theories have varied across jurisdictions, and disputes often turn on how a given state law is written and what, exactly, it restricts.

Where courts land

In broad strokes, courts tend to accept this framework:

• ICE is free to enforce federal law within constitutional limits.
• States are free to choose their level of participation, including choosing very little participation.
• States may not materially interfere with federal operations in ways that conflict with valid federal law, especially where the state is directly regulating federal activity rather than simply managing its own workforce.

That is why the legal fights are so fact-specific. The question is rarely “does immigration belong to the federal government?” It does. The question is “is this state law a refusal to help, or is it a disguised attempt to control the federal program?”

FAQ

Can a state tell its police not to help ICE at all?

A state can usually direct its officers not to participate in federal immigration enforcement tasks, but it cannot forbid what federal law validly requires. The details matter, including whether a state law regulates state employees internally or attempts to penalize third parties for communicating with the federal government.

Does the Supremacy Clause make all “sanctuary” laws unconstitutional?

No. The Supremacy Clause stops state interference with valid federal law. It does not automatically create a duty for states to provide personnel or resources.

Can ICE still operate in the state?

Yes. Federal agents can enforce federal immigration law within constitutional limits, regardless of whether the state chooses to cooperate.

Can local jails refuse ICE detainers?

Often yes, especially if the detainer is a request rather than a warrant and honoring it would extend detention without a sufficient legal basis. The Fourth Amendment and state liability concerns frequently drive these policies.