United States v. State of Illinois

A coalition of 146 cities, counties, and elected officials is pushing back against the Trump administration’s efforts to compel Illinois, Chicago, and Cook County to enforce its harmful immigration policies. On the coalition’s behalf, Public Rights Project filed an amicus brief, arguing the county’s policies are good for their communities.

The brief was filed in a case brought by the U.S. Department of Justice (DOJ), which aims to force Illinois, Chicago, and Cook County to abandon their so-called “sanctuary policies” and engage in federal immigration enforcement. On July 25, 2025, the district court granted the defendants’ motions to dismiss the case. The DOJ appealed the decision.

The brief explains that the U.S. Constitution gives local governments the authority to make decisions about their communities’ police resources. It also highlights the real benefits of so-called “sanctuary policies.”

• They make communities safer by building trust between law enforcement and all residents, so people will report crimes and cooperate with police.
• They strengthen local economies because immigrants play a vital role in the workforce across many industries.
• They support public health by ensuring people can access medical care without fear, protecting community well-being.

Our brief explains why, under existing law, the court should dismiss the case.

In similar challenges, PRP is representing Albuquerque and Boston. We’ve also filed briefs in support of New York City, Minneapolis, four New Jersey cities, and Rochester, New York.

Read the amicus brief.