Democrat Alan Kennedy-Shaffer, a captain in the Colorado Army National Guard and a civil rights attorney, declared on Tuesday that he’s running for Denver’s Senate District 34 seat represented by term-limited Senate Minority Leader Lucia Guzman, D-Denver.

Kennedy-Shaffer, 33, made news recently when he successfully sued President Trump on behalf of a Libyan college student to overturn portions of the president’s travel ban. He also served U.S. Sen. Cory Gardner with subpoenas to appear in court to answer questions about the arrest, at Gardner’s request, of five disability advocates who were staging a sit-in protest at the Republican senator’s Denver office.

Following unsuccessful 2015 bids for the Harrisburg School Board and the Harrisburg City Council in Pennsylvania, Kennedy-Shaffer won an appointment to fill a vacancy on the school board in January 2016. He moved to Denver later that spring to pursue a Ph.D. in public policy at the University of Colorado Denver School of Public Affairs.

“We need progressive leaders who will be out front fighting for justice for all, education for all and healthcare for all,” said Kennedy-Shaffer in a statement. “We must preserve our planet, protect immigrants who make America great, defend women’s rights, worker’s rights and the Constitution. I will fight for you.”

The Senate district is dominated by Democrats, amounting to almost exactly half of the active registered voters, according to the most recent report by the Colorado secretary of state’s office. Just 12 percent are Republicans, and 36 percent are unaffiliated. Guzman won re-election in 2014 with 74.4 percent of the vote over Republican nominee Stuart Siffring, who polled 19.6 percent, and Libertarian candidate Brian Scriber, who received 6 percent of the vote.

Kennedy-Shaffer is the first candidate to announce in the district, although state Rep. Dan Pabon, D-Denver, is said to be considering a run. Pabon didn’t respond to Colorado Politics’ request for comment.

Kennedy-Shaffer has worked as an attorney specializing in criminal justice policy for seven years and serves as a judge advocate, or JAG, with the Colorado Army National Guard. He received his undergraduate degree from Yale University and a law degree from William & Mary Law School in Virginia. He also received a master’s degree from the College of William & Mary.