Endorsements are piling up in the race for Connecticut’s 1st Congressional District as U.S. Rep. John Larson and his three Democratic challengers seek to piece together critical support ahead of Monday’s nominating convention.

That scramble kicked off Thursday morning as former Hartford Mayor Luke Bronin announced the endorsement he secured from Pete Buttigieg, the former U.S. secretary of Transportation and 2020 Democratic presidential candidate.

The two are longtime friends with many similarities: Navy veterans, Rhodes Scholars and former mayors. It could give a boost to Bronin, 46, from a national figure in the Democratic Party who is widely viewed as a potential presidential candidate in 2028.

Buttigieg’s support comes days ahead of the nominating convention, where Larson and his three challengers — Bronin, state Rep. Jillian Gilchrest of West Hartford and Hartford school board member Ruth Fortune — are vying for a spot on the August primary ballot in the Hartford-based district.

By Thursday afternoon, three of the four candidates had rolled out fresh endorsements. Larson said he won the backing of almost a dozen labor unions, former Connecticut lawmakers Chris Dodd and Barbara Kennelly, and state Sen. Matt Lesser of Middletown. Meanwhile, Gilchrest touted support from the online group Progressive Victory.

Bronin and the other challengers, who are a few decades younger than Larson, are making the case for generational change as they take on the 77-year-old incumbent. In his endorsement, Buttigieg noted that Bronin “bring[s] the energy and focus.”

“The Democratic Party needs leaders like Luke Bronin in Congress,” Buttigieg said in a statement. “As a veteran and a mayor, he understands how decisions made in Washington hit people’s everyday lives. He’ll bring the energy and focus that this moment requires to fix a broken system and deliver a more affordable and fair future.”

Buttigieg, the 44-year-old former mayor of South Bend, Ind., became a rising star in the party nearly a decade ago when he made a long-shot bid to lead the Democratic National Committee following the 2016 presidential election.

His profile continued to rise as he ran in the crowded Democratic presidential primary in 2020. Bronin, who was the mayor of Hartford at the time, endorsed his presidential run and campaigned for him. After Joe Biden won the presidency that year, he tapped Buttigieg to serve as the head of the U.S. Department of Transportation.

Bronin and Buttigieg appear to have remained close since then, sharing a table at the 2024 Democratic National Convention when Buttigieg addressed delegates from Connecticut and other New England states. At the time, Bronin told the Connecticut Mirror he was confident a gay candidate could win the White House.

As Democrats search for a winning template and messenger to make gains since their devastating losses in 2024, Bronin on Thursday mentioned Buttigieg’s proclivity for appearing on shows such as Fox News.

“He has the courage to do what more Democrats need to do, which is go anywhere and everywhere — including the most unfriendly territory — and make a forceful case for why Democrats have better answers,” Bronin said. “Whatever role he serves in next, Pete is an important part of the future of the Democratic Party, and his support means a lot.”

The endorsement race has ramped up in recent weeks, especially ahead of next week’s nominating convention. Candidates can secure a spot on the Aug. 11 primary ballot by garnering 15% of delegates at the convention. If they don’t qualify that way, they can also get on the ballot by getting petition signatures from at least 2% of registered Democratic voters in the district.

Larson has touted recent support from the Working Families Party as well as U.S. Rep. Jamie Raskin, D-Md., who notably challenged a more senior member in 2024 to become ranking member of the House Judiciary Committee. U.S. Rep. Jerry Nadler, D-N.Y., eventually dropped his bid. Nadler, 78, announced last year that he’d retire from Congress, saying, “It is the right time to pass the torch to a new generation.”

But in his support for Larson, Raskin said the 14-term congressman from East Hartford is “somebody we need in Washington, and there’s no reason for us to replace him right now in the middle of the biggest fight of our lives.”

While big, splashy endorsements generate headlines and can translate into campaign contributions, candidates will need the support from local leaders and Democrats in the 1st Congressional District at the nominating convention, where they’ll be jockeying for support to get to the 15% threshold.

Earlier this week, Bronin secured endorsements from Barkhamsted’s Democratic Town Committee as well as First Selectperson Meaghan Cook and Selectman Ray Pech.

Larson announced more endorsements on Thursday, including from past and present Connecticut elected officials and 11 unions mainly in the building trades, like the International Brotherhood of Electrical Workers, the International Union of Operating Engineers, the International Union of Elevator Constructors, and the International Union of Bricklayers and Allied Craftworkers.

Lesser is an influential progressive in the state Senate and serves as deputy majority leader. He serves as a co-chair of the Human Services Committee with Gilchrest. But he’s throwing his support behind Larson, whose record he called “unmatched” in supporting the same towns that Lesser represents in his Senate district.

“People are tired of politicians who talk the talk of progressive politics but in the dark of night do the bidding of Wall Street and billionaire financiers. John Larson is the antithesis. He has earned the trust of our district and has never wavered in standing up to special interests to protect the working families of Connecticut,” Lesser said in a statement.

“More than 20 years ago, John Larson was on the right side on the War in Iraq and he has consistently stood up to those in both parties who wanted to weaken or privatize Social Security,” he continued.

Larson also got support from his former colleagues in Congress. That includes Kennelly, who was succeeded by Larson in the U.S. House when she vacated the seat to run for governor in 1998, and Dodd, who served in the U.S. Senate from 1981 to 2011.

Larson’s team is seeking to highlight that the congressman’s “support is grounded in Connecticut, working families, and his colleagues in Congress,” Greg Gerratana, Larson’s campaign manager, said in a statement.

“Voters don’t want a centrist with a corporate, anti-worker agenda. Nothing Luke Bronin and his Wall Street benefactors can do will change that,” he added.

Throughout the campaign, Bronin and Larson have sparred over their labor records. Larson has sought to depict Bronin as hostile to labor during his time as Hartford mayor. Bronin has pushed back, saying that the accusation is false. The two have also repeatedly clashed over where some of their fundraising comes from: Larson getting donations from corporate political action committees and Bronin getting individual contributions from partners and executives for wealth and asset management firms.

Gilchrest has been endorsed by more than a dozen of her colleagues in the state legislature and also has support from some grassroots groups including Indivisible CT and Citizens’ Impeachment.

Her latest endorsement came Thursday from Progressive Victory, a group that says it’s “pushing the Democratic Party to the left.” The organization has so far made 11 endorsements of candidates running for federal office this year. Persephone Hoxha, the New England Lead for Progressive Victory, touted Gilchrest’s “steady guidance toward a more progressive future.”

“For too long, Congress has only worked for the people who can afford to make giant campaign donations or hire an army of lobbyists, while everyone else gets ignored. I’m running to change that,” Gilchrest said in a statement. “It’s not good enough to just say the right thing. The people need results. I’m proud of my record of passing progressive laws and proud to have the support of Progressive Victory and so many allies who share that vision.”