In July 2021, the ACLU, the ACLU of Montana, and the Native American Rights Fund (NARF) filed a class-action lawsuit on behalf of five Indian Nations and 18 individual plaintiffs challenging the state of Montana’s failure to fulfill its constitutional mandate to teach public school students the history and culture of the first peoples of Montana in consultation with local tribes.

The American Civil Liberties Union and the ACLU of Montana filed a federal lawsuit on behalf of two American citizens detained by U.S. Customs and Border Protection for speaking Spanish while shopping at a local convenience store in Havre, Montana.

The American Civil Liberties Union, ACLU of Montana, and Native American Rights Fund challenged a Montana law that severely restricted Native Americans’ access to the ballot. In September 2020, the court issued its ruled for plaintiffs, finding that they presented “cold, hard data” about the law's impact on Native Americans, and how its costs were “simply too high and too burdensome to remain the law of the State of Montana.”