Feds seek to intervene in Wisconsin suit challenging ICE detainers

Listen to this article

In Brief

• U.S. Department of Justice files motion to intervene.
• Case challenges legality of ICE detainers in Wisconsin.
• Sheriffs named include Dave Gerber and Todd Delain.
• ACLU of Wisconsin represents Voces de la Frontera.

MADISON, Wis. – The U.S. government is now seeking to join a case that will determine the legality of ICE detainers in Wisconsin.

Attorneys for the U.S. Department of Justice on Tuesday filed a motion with the state Supreme Court to intervene in the case, which seeks to block county jails from holding immigrant detainees at federal authorities’ request.

The federal government’s effort to join the case seeks to “vindicate its unique and compelling interests in those federal detainers, as well as in the federal cooperative agreements and federal statutory authority at stake in this case,” federal attorneys argued in a brief filed by U.S. Assistant Attorney General Brett A. Shumate and others.

“This cooperation with federal immigration authorities is both longstanding and crucial to enforcement of the Nation’s immigration laws,” the federal attorneys argued.

The U.S. government’s motion comes as the case sits in some jurisdictional uncertainty. It’s currently under the state Supreme Court’s purview, but the sheriffs being sued have also asked a federal appeals court to take it.

The American Civil Liberties Union of Wisconsin filed the lawsuit in September 2025, on behalf of the immigrant advocacy group Voces de la Frontera, against five Wisconsin sheriffs who have partnered with U.S. Immigration and Customs Enforcement to house immigrant detainees, an action known as a detainer.

The state’s highest court agreed to take the case in December 2025, but the five sheriffs named in the lawsuit — 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 – 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, and the sheriffs filed an appeal of Conley’s ruling with the 7th U.S. Circuit Court of Appeals on May 26.

For now, the case remains with the state Supreme Court, where a 4-3 liberal majority will grow to 5-2 when Justice-elect Chris Taylor joins the court in August.

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

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.

Attorney Sam Hall, who represents the sheriffs, has argued throughout the case that the issue should be resolved at the federal judicial level.

“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 the case was sent back to the state Supreme Court.

In a statement, ACLU of Wisconsin attorney Tim Muth accused the sheriffs of using “repeated delay tactics.”

“Each day this case goes undecided, more immigrants are unlawfully arrested by the sheriffs who detain them based solely on ICE’s civil administrative warrants,” Christine Neumann-Ortiz, Voces de la Frontera executive director, said in a statement.

A ruling in Voces de la Frontera’s favor “undoubtedly would impair the United States’ interest in enforcing its immigration laws,” the federal attorneys argued in their brief Tuesday.