Wisconsin ICE detainee lawsuit sent back to state court

MADISON – A lawsuit challenging the legality of ICE detainers in Wisconsin was sent back to the Wisconsin Supreme Court after a failed effort to move the challenge to federal jurisdiction – a decision that may be appealed by the sheriffs named in the case.

The American Civil Liberties Union of Wisconsin filed the lawsuit, which seeks to block county jails from holding immigrant detainees at federal authorities’ request, on behalf of the immigrant advocacy group Voces de la Frontera against five Wisconsin sheriffs who have partnered with the U.S. Immigration and Customs Enforcement agency to house immigrant detainees, an action known as a detainer.

The state’s highest court agreed to take the case in December 2025, but five sheriffs named in the suit then sought to have the case moved to federal court.

U.S. District Judge William Conley on May 15 issued an order remanding the case back to the state Supreme Court, agreeing with Voces’ attorneys that the sheriffs’ removal of the case to federal court did not meet a 30-day deadline for such actions and noting they only sought to do so after learning the state Supreme Court had found the merits of the case worthy of consideration.

“Hopefully, we are closer to the day when local sheriffs and police can no longer detain innocent immigrants without cause until ICE comes to arrest and deport them,” Voces de la Frontera Christine Neuman-Ortiz said in a statement.

The sheriffs being challenged by the ACLU are Dave Gerber of Walworth County, Todd Delain of Brown County, Chad Billeb of Marathon County, David Zoerner of Kenosha County and Chip Meister of Sauk County.

Attorney Sam Hall, who represents the sheriffs, said they are considering the possibility of appealing Conley’s decision to the 7th Circuit Court of Appeals.

“Our position has consistently been that once the Wisconsin Supreme Court directed the parties to address legal issues that clearly encroached on federal law, the federal court became the appropriate forum to resolve those questions. We believe those issues deserve further review,” Hall said in an email.

The case “presents unusual and important legal questions involving the interaction between state authority and federal immigration law,” Hall said, noting that Conley acknowledged in his order that there is no legal precedent “directly controlling” the case’s removal from the state Supreme Court to federal jurisdiction.

“This appears to present an issue of first impression nationally. Beyond impacting this matter, we believe that further guidance from the federal appellate courts may be beneficial to litigants in Wisconsin and nationally,” Hall said.

When a sheriff honors a detainer from ICE, they agree to hold a person for 48 hours after they should have been released under state law to give ICE time to pick up and take custody of the person.

In the lawsuit, the ACLU argues that keeping a person in custody for that extra time constitutes a “new arrest.” It says that’s illegal because Wisconsin law doesn’t allow officers to make civil arrests except in certain circumstances – none of which are relevant to civil immigration enforcement, the group argues.

The group also argues that moving people into federal immigration custody while their local criminal cases are ongoing “disrupts the Wisconsin criminal justice process, potentially depriving victims of justice and defendants of the opportunity to defend against the charges.”

The ACLU is asking the state Supreme Court to declare that civil immigration violations are outside the authority of a law enforcement officer in Wisconsin, and to prohibit the sheriffs from holding people on ICE detainers.

The sheriffs said in their response to the lawsuit last year that their offices have worked with ICE for decades and some have been trained by ICE to serve administrative warrants on their behalf.

The decision to accept the case last year was made by the four liberal-leaning justices who control the court, according to Supreme Court Justice Brian Hagedorn, who is part of the court’s conservative minority. The liberal majority will grow to 5-2 when Justice-elect Chris Taylor joins the court in August.