Court Cases

The ACLU of Colorado sued the Elizabeth School District because it banned and removed at least 19 books from school libraries based on the school board’s disagreement with the ideas they contain. The plaintiffs include students who have a right to access those books.

The ACLU of Colorado filed a class-action lawsuit against the Trump administration to enjoin ICE from conducting warrantless arrests in Colorado without probable cause that the person is a flight risk and in the country without proper legal documentation. On November 25, 2025, a federal judge found ICE had unlawfully arrested each of the named plaintiffs, certified a class of similarly situated individuals, and enjoined ICE from arresting anyone in Colorado without a warrant without first making the probable cause findings required by law.

The ACLU of Colorado filed an Amicus Brief seeking to provide the Court with Colorado-specific context that counsels strongly against eroding the protection provided by a second competency evaluation by an evaluator of the raising party’s choice.

ACLU of Colorado filed a lawsuit against ICE to obtain additional records regarding the agency’s ramp-up plans to expand immigration detention across Colorado and Wyoming. The government has since produced heavily redacted documents revealing some new information about ICE's plans.

The ACLU of Colorado moved to intervene on behalf of Common Cause and individual Colorado voters in a federal lawsuit over the federal government’s demand that Colorado turn over its entire voter registration rolls, including voters’ sensitive personal data.

The ACLU of Colorado filed an amicus brief urging the Colorado Supreme Court to conclude that Colorado state protections preempt municipal sentencing schemes that punish identical conduct more harshly and such schemes violate Colorado’s longstanding equal protection guarantee. On December 22, 2025, the Court held that municipalities may not authorize harsher sentences than state law allows for an identical offense.

The ACLU of Colorado filed a class action lawsuit in federal court seeking to declare that ICE and DHS’s new practice of denying release on bond to groups of noncitizens violates federal law.

The ACLU of Colorado sent a letter to the Superintendent of Littleton Public Schools after being notified that a student was discouraged from sitting in protest during the Pledge of Allegiance.

The ACLU of Colorado filed a lawsuit against an Aurora landlord after repeated threats to report tenants to immigration authorities. The court entered a preliminary injunction ordering the landlord not to threaten, harass, or retaliate our clients, including through disclosure of information about their immigration or citizenship status. The landlord then petitioned for bankruptcy, and the ACLU case is stayed in state court while that proceeding progresses. The preliminary injunction remains in full force and effect.