March/April 2026 Issue

Also in this issue: Welcome Nick Bratsos!     |     Do Municipalities Have to Allow Emotional Support Animals?     |     Welcome Heather Curnutt!

Immigration Enforcement Updates in Wisconsin Municipality Law: Federal Pressure, Local Responses, and Operational Protocols

Jennifer C. Johnson | 03.25.26

Wisconsin has emerged as a focal point in the national debate over immigration enforcement and municipal authority. As the Trump administration intensifies its immigration enforcement agenda throughout 2025 and into 2026, Wisconsin municipalities find themselves navigating unprecedented legal and political pressures. With approximately 70,000 undocumented immigrants residing in the state — many working in critical industries like agriculture and dairy farming — the tension between federal mandates and local governance has profound implications for Wisconsin communities. 

Federal Designation of Wisconsin Jurisdictions 

In May 2025, the Department of Homeland Security (DHS) designated four Wisconsin jurisdictions as ​“sanctuary” areas: the cities of Milwaukee and Madison, along with Dane County and Shawano County. The inclusion was controversial, particularly for Shawano County, where local officials expressed bewilderment at their designation.

Wisconsin’s Legislative Response

Wisconsin’s legislature has responded with competing legislative proposals that reflect deep partisan divisions over immigration enforcement. In October and December 2025, Democratic legislators introduced Senate Bill 493 and Assembly Bill 739, which would prohibit state and local government officials from aiding in the detention of individuals solely based on immigration status. These companion bills specifically target so-called 287(g) agreements, which are federal-local partnerships that authorize local law enforcement to perform immigration enforcement functions. The legislation would bar Wisconsin state agencies and local governmental units, including law enforcement agencies, from entering into or continuing such agreements with the federal government (Wis. Stat. § 20.932).

Additional protective legislation has been introduced to limit state cooperation with federal detention operations. Senate Bill 484 and its Assembly companion would prohibit state agencies, political subdivisions, and county sheriffs from using or permitting the federal government to use state-owned facilities to detain individuals solely based on immigration status (Wis. Stat. § 20.935). The bill would also prohibit expenditure of state or local funds to establish or operate immigrant detention facilities within Wisconsin. These legislative efforts represent an attempt to codify protections similar to those adopted through executive action in other jurisdictions.

Municipal Approaches in Wisconsin’s Largest Cities

At the local level, Wisconsin’s largest cities have taken varied approaches to the sanctuary city designation. Milwaukee Mayor Cavalier Johnson has explicitly declined to declare Milwaukee a sanctuary city. Dane County has taken more proactive steps, with Sheriff Kalvin Barrett announcing earlier in 2025 that his department would no longer participate in the federal State Criminal Alien Assistance Program (SCAAP), which had required sharing immigration data with federal authorities (WPR, 2025).

Constitutional Protections for Municipalities Under the Tenth Amendment

Cooperation between the federal government and state and local jurisdictions is voluntary, a prerogative of the state or locality, not a legal obligation. As a matter of constitutional law, the Tenth Amendment of the U.S. Constitution limits the federal government’s authority to require states and localities to carry out immigration enforcement activities. Id. As Justice Antonin Scalia wrote for the majority in Printz v. United States, 521 U.S. 898, 925 (1997), the Tenth Amendment creates an anti-commandeering doctrine that limits federal authority over local officials: ​“The Federal Government may neither issue directives requiring the States to address particular problems, nor command the States’ officers, or those of their political subdivisions, to administer or enforce a federal regulatory program. Such commands are fundamentally incompatible with our constitutional system of dual sovereignty.”

In essence, the anti-commandeering doctrine says that the federal government cannot require states or municipalities to directly carry out or enforce federal enforcement policies, including immigration law. This doctrine has been upheld in many landmark cases, including Murphy v. NCAA, 584 U.S. 453, 470 (2018), in which the Supreme Court concluded that Congress lacks ​“the power to issue orders directly to the States.”

This means Wisconsin municipalities can legally decline to assist with federal immigration enforcement operations, refuse to honor ICE detainers without judicial warrants, and establish sanctuary policies without violating federal law. Because the federal government is unable to commandeer state and local officials to carry out federal immigration enforcement activities, it is a constitutional prerogative for states and municipalities to set their levels of collaboration with federal immigration agencies.

How Wisconsin Municipalities Should Respond When ICE Arrives

The most critical operational challenge facing Wisconsin municipal officials is knowing how to respond when Immigration and Customs Enforcement agents arrive at government facilities. Recent developments in federal policy have made this issue particularly urgent and complex.

Understanding Warrant Types

Municipal officials must understand the crucial distinction between judicial and administrative warrants. A judicial warrant is issued by a court and signed by a judge, authorizing entry into private, non-public spaces. An administrative warrant, by contrast, is issued by ICE itself without judicial review and traditionally has not authorized entry into areas where there is a reasonable expectation of privacy. However, a controversial May 2025 ICE memo claimed authority for agents to forcibly enter homes using only administrative warrants departure from decades of agency policy that has raised serious Fourth Amendment concerns.

Recommended Protocols for Government Facilities

Wisconsin municipalities should establish clear protocols for when federal immigration enforcement arrives at municipal buildings:

• Designate Point Personnel: Municipalities should designate specific staff members — typically legal counsel, city managers, or senior department heads — to serve as the primary contact when ICE agents arrive. Front-line employees such as receptionists should be trained to immediately contact designated personnel rather than making independent decisions about access.
• Verify Agent Identity and Documentation: Staff should request proper identification from all agents and carefully examine any warrant presented. Officials have the right to read the warrant thoroughly to determine whether it is judicial or administrative, verify that it is properly signed, confirms it names the correct person or location, and ensure it is within the valid execution timeframe.
• Know Your Rights Regarding Access: ICE generally does not need permission to enter public areas of government buildings, such as lobbies or waiting rooms. However, to enter non-public areas such as offices, employee break rooms, or restricted spaces, ICE needs either explicit permission from the municipality, a subpoena, or a judicial warrant (Minnesota AG, 2025). Administrative warrants alone do not authorize entry into non-public spaces without consent.
• Document All Interactions: Municipal staff should thoroughly document encounters with federal agents, including recording names, badge numbers, agency affiliations, time of arrival and departure, areas accessed, and any statements made. Audio or video recording of interactions is permissible.
• Protect Employee and Visitor Information: Unless presented with a judicial warrant or subpoena, municipalities should not provide sensitive information that is not generally available to the public, such as employee schedules, home addresses, or release dates for individuals in municipal custody.
• Do Not Consent Without Legal Review: Municipal representatives should not sign any documents or provide consent to searches of non-public areas without first consulting with legal counsel. Staff should clearly state if they do not consent to a search while avoiding physical obstruction of federal agents.
• Maintain Constitutional Protections: Wisconsin municipalities have no obligation under the Tenth Amendment to assist with federal immigration enforcement (Minnesota AG, 2025). Local officials should be aware that courts have held that the federal government cannot commandeer state and local resources for immigration enforcement purposes.

Conclusion

As 2026 unfolds, Wisconsin municipalities must carefully navigate legal constraints, fiscal pressures, and community values while protecting the constitutional rights of all persons within their jurisdiction. By establishing clear protocols for responding to federal enforcement actions, Wisconsin communities can uphold the rule of law while maintaining their commitment to public safety and community trust.