Former Colorado Gov. Bill Ritter, a leader in the push for clean energy, on Monday endorsed Joe Neguse, one of three Democrats running for the 2nd Congressional District seat, saying the former University of Colorado regent will lead the fight against climate change.

“I’ve known and worked with Joe for over a decade – he is a public servant deeply committed to working with others to solve tough problems. Joe will be a passionate champion for protecting our environment and leading the fight against climate change, and will be a tireless advocate for the people of Colorado,” said Ritter, a Democrat and the director of Colorado State University’s Center for the New Energy Economy, in a statement.

Neguse said he was honored to have the support of Ritter, who coined the phrase “new energy economy,” calling him a champion for protecting the environment.

“One of the central reasons I am running for Congress is because we must take immediate action to reduce the catastrophic effects of climate change and move our country towards 100-percent clean and renewable energy,” Neguse said in a statement.

During his one term as governor, Ritter signed legislation to require that certain utilities obtain 30 percent of their  power from renewable sources, as well as the Clean Air Clean Jobs Act – critics argued it promoted neither – which pushed utilities away from coal toward natural gas.

Ritter’s endorsement on Martin Luther King Jr. Day highlights the possibility Neguse, the son of Eritrean immigrants, would become the first African-American sent to Congress from Colorado if he’s elected in November.

At 33, Neguse, an attorney, would also be one of the youngest members of Congress. He stepped down last year as executive director of Colorado’s Department of Regulatory Agencies when he announced his candidacy. A co-founder of New Era Colorado, the left-leaning group that encourages young state residents to register and vote, Neguse lost a run for secretary of state in 2014 to Republican Wayne Williams.

Neguse has won the backing of other prominent environmental groups and leaders, including the League of Conservation Voters Action Fund, Boulder Mayor Suzanne Jones and Leslie Glustrom, director of research at Clean Energy Action.

He’s also been endorsed by every Democratic legislator from Broomfield, Clear Creek, Gilpin, Summit, Grand and Larimer counties – along with the less densely populated portions of western and southern Jefferson County and portions of Park County, the components of the 2nd District.

Two other Democrats are running for the seat, which has been occupied since 2009 by Democrat Jared Polis, a candidate for governor – Nederland Mayor Kristopher Larsen and former Boulder Democratic Party Chairman Mark Williams. Gun control activist Ken Toltz suspended his campaign for the Democratic nomination last month. Republican Peter Yu, a political newcomer, is seeking his party’s nomination.