U.S. Rep. Seth Moulton, a moderate Massachusetts Democrat, secured enough delegate support Saturday to appear on the state's primary ballot as he challenges incumbent Sen. Ed Markey in this year's Senate race.

Yet even though Moulton cleared a key hurdle to continue his Senate bid, it was Markey who won the party's endorsement after winning more than 50% of the delegation's support.

"You have a choice, you have to decide what the future looks like and what you're going to demand," Markey said Saturday in front of more than 4,000 delegates.

The Massachusetts primary is Sept. 1. 

Markey won nearly 73% of the delegates' support, while Moulton won nearly 27% of the vote. Massachusetts Democratic Party rules require statewide candidates to get at least 15% of delegate support to appear on primary ballots.

In heavily Democratic Massachusetts, the Senate primary contest is one of the most closely watched in the country as Moulton, 47, has centered his campaign on changing the status quo and demanding a generational shift in leadership. 

If reelected, Markey would be 80 before his third six-year term would begin. While Markey has touted his stamina and embrace of progressive policies, questions about age have continued to swirl around Democratic candidates as they fight to take back control of Congress.

In his nomination speech, Moulton argued that the Democratic Party needed more than "incremental change" and needed to start anew.

"It's time for the generation that grew up with the internet, and will have to live for decades with AI, to lead our way through it," Moulton said.

Moulton only addressed his opponent briefly during his nomination speech, giving a passing nod on not waiting another six years for generational change and later calling on Markey to participate in multiple debates before the September primary. Currently, the two candidates have agreed to participate in one debate later this summer.

Markey, instead, took a more critical approach by attacking Moulton's previous comments about transgender kids and accepting corporate PAC money.

"Massachusetts deserves better than a senator who scapegoats trans kids," Markey said to loud cheers.

In 2024, Moulton caught flak from some members of his party for saying he didn't want his daughters playing in sports against transgender girls. Critics said Moulton echoed President Trump's talking points against allowing transgender athletes in girls' and women's sports.

Moulton has since said his intent with that statement "was to point out that, as a party, we need to be willing to have difficult conversations."

Moulton, who enlisted in the Marines after the Sept. 11, 2001, attacks and served four tours of duty in Iraq, was first elected to the House in 2014. He briefly launched a 2020 presidential campaign, but he dropped that bid after a few months.

Markey served as a Massachusetts congressman for nearly 40 years before winning the Senate seat in 2013. He fended off a challenge in 2020 from Rep. Joe Kennedy III in the Senate primary by turning to his progressive allies to overcome a challenge from a younger rival from America's most famous political family.