Wisconsin Supreme Court to Decide Whether Local Jails Can Honor ICE Detainers

The Wisconsin Supreme Court has agreed to decide whether state law prohibits county jails from holding people at the request of federal immigration authorities — a question with implications for cooperation between local law enforcement and U.S. Immigration and Customs Enforcement (ICE).

The case was filed directly with the high court in September by immigrant-rights group Voces de la Frontera and challenges the practices of five county sheriffs who have honored civil detainer requests from ICE. The court, which now has a 4-3 liberal majority, accepted the direct appeal; a direct filing requires the support of at least four justices. The court did not disclose the vote breakdown, although conservative Justices Annette Ziegler and Rebecca Bradley publicly dissented from the decision to take the case.

Conservative Justice Brian Hagedorn issued a separate statement — without revealing how he voted — warning that publicly dissenting at the procedural stage departs from a long-standing court practice and risks creating the impression that some justices have pre-judged the merits of politically charged cases before briefing is complete.

Legal dispute

The ACLU of Wisconsin, representing Voces de la Frontera, contends that under state law keeping a person in custody after they are entitled to be released amounts to a new arrest, and that sheriffs therefore lack authority to hold people on the basis of ICE's civil detainers. Wisconsin statutes largely bar law enforcement from making arrests for civil matters, the complaint says. ICE detainers are voluntary requests asking local jails to hold individuals up to 48 hours beyond their release time so federal agents can assume custody.

"ICE continues to send hundreds of these detainers to Wisconsin jails, and people throughout the state are being illegally held for days so that ICE can pick them up," said Timothy Muth, an attorney for Voces de la Frontera and counsel at the ACLU of Wisconsin.

Lawyers for Voces de la Frontera asked the Supreme Court to expedite review, alleging that in the first seven months of 2025 ICE issued more than 700 detainers to local jails in Wisconsin and that at least 247 people were unlawfully held as a result.

Sheriffs' response

The sheriffs asked the court not to accept the direct appeal, arguing they have a long practice of cooperating with ICE and that there was no need to bypass lower courts. They also maintain the state statute cited by the plaintiff does not apply when sheriffs act in coordination with federal immigration authorities.

Samuel Hall, who represents four of the sheriffs at Crivello, Nichols & Hall, said the attorneys were reviewing the court's order and considering 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," Hall said. Andrew Phillips of Attolles Law also represents the sheriffs.

The U.S. Department of Homeland Security, which oversees ICE, has not filed a position in the case and did not respond to requests for comment.

Case: Voces de la Frontera v. Gerber, Wisconsin Supreme Court No. 2025AP002121. For Voces de la Frontera: Timothy Muth (ACLU of Wisconsin). For the sheriffs: Samuel Hall (Crivello, Nichols & Hall) and Andrew Phillips (Attolles Law).