The longtime legal director of the American Civil Liberties Union’s Colorado branch on Wednesday announced his upcoming retirement after 26 years.

Mark Silverstein, who has been the face of every case the ACLU of Colorado has been involved with for the past two-and-a-half decades, will step into the role of legal director emeritus, the organization announced.

He will stay in his current role while the organization searches for a new legal director. Silverstein worked as a staff attorney for the ACLU of Southern California for five years before his role in Colorado.

“Working as an ACLU lawyer and Legal Director is one of the very best jobs an attorney could have,” Silverstein said in a news release. “It has been a privilege and a lucky break for me to get to spend so many years working in an organization filled with so many dedicated civil libertarians and alongside some of the most talented lawyers in Colorado and in the country.”

During Silverstein’s time heading Colorado’s legal work, the ACLU has taken on many high-profile civil rights cases. The organization reached a settlement in a class-action suit filed in 2002 to end a practice by the Denver Police Department of surveilling people involved in peaceful protests and activist work, labeling them in police files as extremists.

Another case filed in 2018 accused El Paso County’s sheriff of violating state law by refusing to release people who had posted bond or finished their sentence, at the request of federal immigration officials. The ACLU obtained a permanent injunction against the practice.

And recently, the ACLU represented several protesters involved in an excessive force lawsuit against Denver for the police’s handling of the city’s 2020 racial justice protests. A jury awarded the group $14 million.

“Mark has long been known as one of the most effective lawyers in the ACLU,” David Fathi, director of the ACLU National Prison Project, said in the release. “He’s everything you could ever want in a colleague: smart, collaborative, hardworking, and fiercely dedicated to the clients we serve.”