The Wisconsin Supreme Court has agreed to hear a case challenging whether Wisconsin sheriffs have the power under state law to honor federal immigration detainers.
Earlier this month, a divided Wisconsin Supreme Court decided to hear the case, Voces de la Frontera v. Gerber, brought by the American Civil Liberties Union on behalf of an immigrant rights group.
If the high court rules that local law enforcement cannot honor ICE holds, it essentially means Wisconsin could become a sanctuary state.
The lawsuit is part of a larger nationwide strategy to get states with liberal majorities to use the courts to block local law enforcement from assisting with immigration enforcement.
The timing is also suspect given an impending Wisconsin Supreme Court election in April 2026 to fill an open seat being vacated by conservative Justice Rebecca Bradley.
Hearing a case on illegal immigration could shake things up or change the makeup of the bench in the battleground state.
Wisconsin Court of Appeals Judge Maria Lazar entered the 2026 race on Oct. 1. Lazar, a conservative, promised to stop the politicization of the courts after record-high spending in the 2025 race, fueled by billionaires Elon Musk and George Soros.
The majority of deportations stem from an illegal immigrant getting arrested and charged with a crime. Common crimes include traffic offenses, drunk driving, domestic abuse, battery or sexual assault.
In Wisconsin, like most states, county jails are run by sheriffs. Once an illegal alien is booked into the county jail, and ICE learns of the arrest, the agency will issue an immigration detainer.
Honoring an ICE detainer means the sheriff agrees to hold the person for 48 hours after they otherwise should have been released under state law.
The ACLU has argued that it is illegal for local jails to hold immigrant detainees at the request of federal authorities. The lawsuit was filed against sheriffs in Walworth, Brown, Marathon, Kenosha and Sauk counties, all of which honor those requests, the AP reported.
Similar lawsuits in states with left-leaning courts have been filed and succeeded elsewhere, such as Minnesota, New York, Montana, Massachusetts and Colorado.
The lawsuits use the same tactic by getting the high court to declare that state law prohibits state cooperation with ICE detainers, according to The Federalist.
A majority of justices on the Wisconsin Supreme Court voted to take the ACLU case directly as an original action, rather than have it first work its way through lower courts.
Four justices, who were not named, voted to accept the case, while conservative Justices Annette Ziegler and Rebecca Bradley dissented, the Associated Press reported.
Sam Hall, one of the attorneys for the sheriffs, told the AP they were reviewing the court’s order and evaluating next steps.
“We are confident, however, that Wisconsin sheriffs who honor ICE detainers do so fully within the bounds of Wisconsin law and the federal legal framework governing immigration enforcement,” he said in an email.
Commonly known as an ICE hold, a detainer asks a federal, state or local law enforcement agency — including jails, prisons or other confinement facilities — to keep the alien for up to 48 hours after they otherwise should have been released to give ICE more time to arrange for pickup.
The petitioners in the Wisconsin case want the court to weigh in on whether Wisconsin sheriffs have the authority to make a civil arrest pursuant to a federal immigration detainer.
According to the ACLU lawsuit, honoring an ICE detainer and keeping the person in custody for that extra time constitutes an illegal new arrest.
In addition, immigration violations are essentially a civil offense not a criminal one. Wisconsin law enforcement does not have the authority to make arrests based solely on ICE’s civil administrative “warrants.”
The ACLU argues that holding someone for extra time must be authorized by a judicial warrant, in which a court determines there is probable cause to keep them longer.
But the argument is not as straightforward as the petitioners would like, according to Dan Lennington, managing vice president and deputy counsel at the Wisconsin Institute for Law & Liberty.
“And, so, a sheriff honoring a detainer is agreeing to exercise delegated federal power and hold that alien pursuant to federal law,” Lennington said. “This is simply a federal-state agreement, which is a common feature of modern law enforcement.”
The Trump administration has focused on expanding 287(g) agreements with local sheriff’s departments. In Florida, all 67 Florida sheriffs are now part of the 287(g) program. Wisconsin has 13 counties with these agreements, Lennington noted.
In counties that participate in the program, it means the jail automatically checks all names booked into the jail against the federal ICE database. ICE issues a detainer if there is a hit that the individual is wanted for an immigration violation.
But whether an agreement exists or not, nearly all Wisconsin counties cooperate with ICE and honor detainers other than the sanctuary cities of Madison and Milwaukee.
The Federalist reported that “ICE detainers are common in Wisconsin.” The state’s Democratic Gov. Tony Evers actually has a policy mandating that the state Department of Corrections comply with ICE holds.
Immigrant rights’ activists and groups such as the ACLU describe it as the “Jail-to-Deportation Pipeline.” According to a recent report by the ACLU, there were 1,065 holds issued to Wisconsin jails in the first five months of 2025.
However, under state law, Wisconsin sheriffs have independent legal authority to enter into cooperative agreements with federal agencies.
If the Wisconsin Supreme Court should rule that sheriffs don’t have the authority to honor federal ICE detainers or enter into agreements with federal partners, “then that holding would jeopardize many existing relationships between state and federal agencies (and the funding that comes with it),” according to Lennington.
Beyond that, sheriffs have the authority to hold individuals based on probable cause that a crime has been committed. Since it is crime to enter the United States without permission, by nature of an alien being unlawfully presence, it would give them probable cause to hold them.
Additionally, under 8 U.S.C. § 1226, illegal aliens who violate state criminal laws are considered “criminal aliens” under federal law. Being undocumented also means they failed to register, which is a crime in violation of 8 U.S.C. § 1302. ICE.
However, in 2025, leftists and activists are working overtime to thwart the Trump administration’s immigration agenda. George Soros-backed judges and Democratic prosecutors and politicians like to play dirty by wielding power through the judicial branch.
And despite Wisconsin flipping red during the 2024 election, it was the only state to be decided by less than a 1% margin. The Wisconsin Supreme Court has a solid liberal grip with a 4-3 majority.
“The fact that the court granted this request is a sign that it wants to grant the relief requested by petitioners,” according to Lennington’s take on the case. “They could have allowed this case to percolate in the lower court, ironing out all the complicated factual issues presented by the federal policy. But they didn’t.”
Republicans in the GOP-controlled Wisconsin Legislature support a bill that would withhold money from counties that don’t comply with ICE detainers. The measure passed the Assembly, and if the Senate approves the bill it would head to Evers, who is likely to veto it, the AP reported.
The U.S. Department of Homeland Security has yet to announce a major enforcement effort in Wisconsin despite some high-profile stories of illegal aliens tied to criminal activity.
And a Supreme Court ruling that would effectively turn Wisconsin into a sanctuary state and shut down local sheriff’s departments and county jails from working with ICE could result in more ICE agents in the state.
According to local reports, a Milwaukee suburb has been targeted by highly organized gang of illegal immigrant burglars. In September, ICE arrested 24 illegal aliens in Manitowoc County, Wis., with suspected ties to a transnational human trafficking and drug trafficking ring.
Depending on the Wisconsin’s high court ruling, the case could make its way to the U.S. Supreme Court.
The Trump administration has not intervened in any of the previous state cases, but it could in this instance because “the case raises the issue of federal preemption, which the Wisconsin Supreme Court tacitly acknowledges with their reference to 287(g) agreements in the briefing order,” Lennington noted.
