Wisconsin Supreme Court to review local jails' compliance with ICE detainer requests

December 3 The Wisconsin Supreme Court has agreed to examine whether state law prevents local jails from holding individuals at the request of federal immigration authorities. This case could affect federal efforts to increase deportations in Wisconsin.

The court, currently holding a 4-3 liberal majority, will review a lawsuit filed by the immigrant rights organization Voces de la Frontera in September. The suit challenges the practice of five county sheriffs who have been honoring civil detainer requests from U.S. Immigration and Customs Enforcement (ICE).

At least four justices are required to approve hearing a case filed directly with the Supreme Court rather than proceeding through lower courts. While the court did not disclose the full vote, conservative Justices Annette Ziegler and Rebecca Bradley publicly opposed hearing the case. Conservative Justice Brian Hagedorn issued a separate statement cautioning that public dissent at this stage could give the impression that justices have already decided on the cases merits.

Timothy Muth, attorney for Voces de la Frontera with the American Civil Liberties Union of Wisconsin, praised the decision. "ICE continues to issue hundreds of detainers to Wisconsin jails, leading to individuals being unlawfully held for days," he said. The lawsuit targets sheriffs offices in Walworth, Brown, Kenosha, Sauk, and Marathon counties. The ACLU argues that detaining someone when they are legally entitled to release amounts to a new arrest, and Wisconsin law does not authorize sheriffs to hold individuals on civil ICE detainers.

This case follows a trend of legal challenges in multiple states questioning the cooperation of local law enforcement with ICE. Courts in Massachusetts, Montana, Minnesota, and New York have previously limited or prohibited local authorities from detaining individuals based on federal immigration detainers, which are voluntary requests to hold individuals up to 48 hours past their release date for ICE custody.

Voces de la Frontera has asked the Wisconsin Supreme Court to fast-track the case, citing that ICE issued over 700 detainers in the first seven months of 2025, resulting in at least 247 unlawful detentions. The federal government has not commented, and the Department of Homeland Security did not respond to requests for input.

In an October brief, the sheriffs argued against the court hearing the case, claiming longstanding cooperation with ICE and disputing the relevance of the state law cited by the plaintiff. Samuel Hall, representing four of the sheriffs, stated that they are reviewing the courts order and are confident their compliance with ICE detainers is lawful under Wisconsin and federal law.

The case is Voces de la Frontera v Gerber, Wisconsin Supreme Court, No. 2025AP002121.

Analysis: Wisconsin Supreme Court to Weigh in on ICE Detainer Controversy

The Wisconsin Supreme Court's decision to review the case brought by Voces de la Frontera highlights a critical legal challenge to the relationship between local law enforcement and federal immigration authorities. At the heart of this case is whether state law allows county sheriffs to hold individuals at the request of U.S. Immigration and Customs Enforcement (ICE). The outcome could have significant implications for future immigration enforcement practices in the state.

The lawsuit, filed by immigrant rights advocates, targets five Wisconsin counties where local sheriffs have been honoring ICE’s civil detainer requests. These requests allow federal authorities to extend a detainee's time in jail beyond their scheduled release, up to 48 hours. However, Voces de la Frontera and the American Civil Liberties Union argue that such detentions violate Wisconsin law, which does not authorize sheriffs to hold individuals beyond their release date solely based on ICE detainers.

In the broader context, this case joins a growing trend of legal challenges across the United States questioning the practice of local law enforcement collaborating with ICE. Several states, including Massachusetts and New York, have already imposed limitations on the use of ICE detainers. The Wisconsin case could thus serve as a bellwether for how other jurisdictions might approach this complex intersection of local and federal authority.

As the Wisconsin Supreme Court deliberates, the stakes are high. Local jails across the state have seen hundreds of detainers issued in recent years, and the impact on immigrant communities is significant. With the potential to redefine how local authorities engage with federal immigration policies, this case will likely influence both legal and political discussions on immigration enforcement nationwide.

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• Wisconsin top court to examine if local jails can comply with ICE detainer requests