Rep. Maxwell Frost, a Florida progressive and the first Gen Z member of Congress, endorsed Angela Alsobrooks for Senate in Maryland, where she is running to become the state’s first Black female U.S. senator.

“We need bold progressive fighters who are going to help make sure that we usher in an agenda of ending gun violence, of defeating the climate crisis and of centering vulnerable communities,” Frost told HuffPost. “When we talk about someone like Angela Alsobrooks, she’s been doing the work time and time again.”

Frost’s endorsement is the latest escalation of the intra-party brawl brewing in Maryland, where there’s a suddenly competitive race for an open seat that should be a shoo-in for Democrats.

Alsobrooks, the county executive for Prince George’s County, is pitted against Rep. David Trone in the May contest for the Democratic nomination. Both candidates have rolled out extensive slates of endorsements from different wings of the party, with Frost, a progressive, being the latest get for Alsobrooks, who also has the backing of members of the Congressional Black Caucus and a majority of Maryland’s congressional delegation. Trone, meanwhile, has a coalition of moderate congressional Democrats behind him, including Rep. Adam Schiff, who is well-positioned to become California’s next U.S. senator in November.

Frost, a former national organizing director for the youth-led anti-gun violence group March for Our Lives, was driven to run for office following the 2018 shooting at Marjorie Stoneman Douglas High School in Parkland, Fla. In 2022, Frost, now 27, became the first member of Gen Z elected to Congress.

Alsobrooks, 53, told HuffPost she shares Frost’s commitment to gun safety measures, including an assault weapons ban. “I have spent now a good portion of my career working to keep families safe,” Alsobrooks said, adding she and Frost “share in common a philosophy, which is that you don’t get to sit on the sidelines.”

“I also know that the congressman was spurred to action based on his concern for safety, and that’s literally how I got into elective office in 2010. I was concerned about the world that my daughter was growing up in,” she said. “Gun violence in our country at this point is an epidemic, and I think in order to solve it, we need a broad coalition working on it.”

Alsobrooks served two terms as the state’s attorney for Prince George’s County in suburban D.C. before becoming its county executive in 2018.

Trone, the founder and co-owner of Total Wine & More, won his first U.S. House race in 2018. He’s drawn millions from his personal fortune to fund his races, including more than $23 million in the primary against Alsobrooks. Trone argues he offers tested leadership and can’t be bought by PACs and similar influence peddlers.

If elected, Alsobrooks would be the first Black woman elected to represent Maryland in the Senate, which has only ever had two Black women as members. Maryland also has the sixth-largest Black population percentage-wise in the nation. Frost, who is multiracial, says Alsobrooks would give a necessary voice to the state’s diverse electorate.

“Having her perspective there and having her fight there is going to directly benefit every person in Maryland,” Frost said.

Maryland’s open Senate race to replace retiring Democrat Ben Cardin is suddenly competitive not only in the primary: Last month, former Maryland Gov. Larry Hogan, a popular Republican, made a surprise comeback, potentially scrambling the general election map for Democrats. The party is almost guaranteed to lose a seat this year with the retirement of Sen. Joe Manchin in West Virginia, and is defending vulnerable members in Ohio and Montana.

Hogan defied the conventional politics of deep-blue Maryland as its two-term GOP governor, making him the only formidable opponent for Democrats. He’s the heavy favorite to emerge from his own primary on May 14.

“I’m the person who is best equipped to defeat Larry Hogan in a general election and this is because of the support of people like Congressman Frost,” Alsobrooks said. “We are going to have to engage younger voters, engage women ... I think we need candidates who are inspirational and who are able to inspire people to come out and to participate.”