A federal judge has ruled that a high-profile lawsuit challenging the legality of county sheriffs honoring federal immigration detainers will remain in the Wisconsin Supreme Court, prompting attorneys for five sheriffs to consider an appeal to the 7th U.S. Circuit Court of Appeals.
The case, Voces de la Frontera, Inc. v. Dave Gerber, et al., was originally filed in September 2025 directly with the Wisconsin Supreme Court by the ACLU of Wisconsin on behalf of the immigrant advocacy group Voces de la Frontera. It questions whether Wisconsin sheriffs have the legal authority under state law to hold individuals in custody for up to 48 hours beyond their scheduled release date at the request of U.S. Immigration and Customs Enforcement (ICE).
U.S. District Judge William Conley rejected the sheriffs’ request to move the lawsuit from state court to federal court. He decided that the heart of the dispute is about Wisconsin state law — specifically, when and how local sheriffs are allowed to make arrests — rather than federal immigration law.
The May 18 ruling means the case will continue in the Wisconsin Supreme Court.
Sam Hall, an attorney with Crivello, Nichols & Hall, S.C., who represents the five sheriffs named in the suit, told the Milwaukee Journal Sentinel that his clients respectfully disagree with the decision and are evaluating whether to appeal to the 7th Circuit.
“We are considering all options, including an appeal to the Seventh Circuit Court of Appeals,” Hall said in coverage of the ruling.
The lawsuit argues that honoring ICE detainers effectively constitutes an arrest under Wisconsin law, which requires probable cause or a warrant — something a civil immigration detainer does not provide. Plaintiffs argue the practice violates state statutes governing when and how long local law enforcement can detain people.
Supporters of the sheriffs’ position maintain that cooperating with ICE on detainers is a vital tool for public safety and immigration enforcement, especially in communities dealing with repeat offenders or individuals with serious criminal histories.
The Wisconsin Supreme Court had accepted the original filing, bypassing lower state courts due to the statewide significance of the issue. If the case proceeds there, it could result in a definitive ruling on whether — and under what circumstances — Wisconsin sheriffs may continue the long-standing practice of honoring ICE detainers.
As of Tuesday, no appeal had been formally filed in the 7th Circuit, but Hall indicated his clients are actively weighing their next steps following Judge Conley’s decision.
