MADISON, Wis. — A divided Wisconsin Supreme Court on Wednesday agreed to take a case brought by the American Civil Liberties Union on behalf of an immigrant rights group arguing that it is illegal for local jails to hold immigrant detainees at the request of federal authorities.
The Wisconsin lawsuit comes as federal agents have launched high-profile immigration crackdowns in cities including Chicago and Charlotte, North Carolina. Another operation is expected in the coming days in Minnesota, targeting Somali immigrants. The enforcement tactics have been met with protests and lawsuits.
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. The court is controlled 4-3 by liberal justices.
Four justices, who were not named, voted to accept the case, while conservative Justices Annette Ziegler and Rebecca Bradley dissented. Justice Brian Hagedorn, who most often sides with conservative justices, wrote separately to discuss the process, but he did not reveal how he voted.
None of the justices discussed the merits of the case in the order agreeing to take it.
The court's decision means there could be a final ruling in the case by the middle of 2026, far faster than if it first had to wind its way through lower courts. All briefs in the case are due within two months, and the court will set a date for oral argument sometime after that early next year.
The ACLU brought the lawsuit against five county sheriffs in September on behalf of Voces de la Frontera, an immigrant rights group based in Milwaukee.
"This is a historic step toward ensuring that Wisconsin's law protects all residents, not just those with power and privilege," said Christine Neumann-Ortiz, executive director of Voces de la Frontera. "Honoring ICE detainers has subjected hardworking immigrants to unlawful arrests for far too long."
The lawsuit contends that it is illegal for local jails to hold immigrants on detainers sent by U.S. Immigration and Customs Enforcement to local sheriff's offices. The lawsuit was filed against sheriffs in Walworth, Brown, Marathon, Kenosha and Sauk counties, all of which honor those requests.
Sam Hall, one of the attorneys for the sheriffs, said 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.
The sheriffs had argued that because the lawsuit involves a complicated area of the law — federal immigration law and the relationship between federal and state and local law enforcement — the case was best "resolved and refined" by first going through the lower courts, rather than skipping directly to the Wisconsin Supreme Court.
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 goal of detainers is to give ICE agents more time to pick someone up if they are suspected of being in the country illegally.
The ACLU wants the Wisconsin Supreme Court to prohibit sheriffs from holding people on ICE detainers, which are based on administrative warrants. 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, the ACLU argues in the lawsuit.
The ACLU argues that keeping the person in custody for that extra time constitutes an illegal new arrest. It is illegal because Wisconsin law does not allow officers to make civil arrests except in certain circumstances, none of which apply to immigration enforcement, the lawsuit argues.
In the first seven months of this year, ICE sent more than 700 requests to local jails across Wisconsin, asking them to hold someone 48 hours beyond when they were set to be released, the lawsuit contends.
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 Democratic Gov. Tony Evers, who is likely to veto it.
