Congressman John B. Larson relied on familiar themes, faces and places Friday as he arrived in a union hall in East Hartford to begin a campaign unlike 13 previous runs for reelection: At 77, Larson faces his first serious challenge for the Democratic nomination since winning an open seat in 1998.

Campaign kickoffs are theatrical pieces, and Larson’s featured themes of loyalty, experience and seniority — attributes that made challenges unthinkable in other years in Connecticut, a state historically hostile to primaries against incumbent Democrats.

As the congressman stepped to a microphone on a crowded riser to formally become the fifth Democrat to declare their candidacy in the 1st Congressional District, a snippet of a 1970s pop hit played: “We’re still having fun, and you’re still the one.”

Both notions have been tested this summer. Four challengers, including former Hartford Mayor Luke Bronin and state Rep. Jillian Gilchrest of West Hartford, opened campaigns that found no fault with Larson’s liberal, pro-labor voting record but insisted the time had come for new leadership in a struggling Democratic Party.

Larson ignored his challengers to focus on a desire to return to Washington for a 29th and 30th year to fight President Donald Trump on immigration, gun control, student debt, health care, women’s rights, climate and the congressman’s favorite issue, the preservation of Social Security.

“It’s time for Democrats to unite and stand together, because we’re in a fight. You know it, and I know it. So I ask you, are you ready for a fight?” Larson said, pausing briefly for the certain affirmative answer. Smiling, he added, “I officially announce my campaign for congressman from the First District.”

He promised action on his agenda in the first 100 days after Democrats retake the majority in the House, though Republicans would still control the White House and  most likely the Senate.

East Hartford is home to Larson and his large extended family. He began his career more than 45 years ago as a school board member, then was elected to the council and state Senate. His brother, Tim, is a former mayor and state senator. He grew up in Mayberry Village, public housing.

The current mayor, Connor Martin, once worked at Goodwin University for another Larson brother, Dan Larson. And Larson was introduced by his niece, Arianna Larson. To launch the campaign, he chose a familiar setting, the International Association of Machinists hall across the street from Pratt & Whitney.

“The thing about a big family and loyal friends — when you attack one of us, you attack all of us, and we stick together,” Larson said.

An old friend, U.S. Rep. Jim Clyburn of South Carolina, sat in the front row near Joe Suggs, a retiree who competed with Larson for the congressional seat in the 1998 primary. Kevin Sullivan, a former state Senate leader and lieutenant governor, also came to show support, as did former state Sen. Eric Coleman. Sullivan and Coleman are in their 70s. Clyburn is 85.

Martin, the mayor, turns 34 next week. He said the congressman and two of his brothers have been mentors.

“His story is not very different than mine, and probably many of us in the room, growing up in public housing, right? Not having generational wealth, right?” Martin said. “His family, having to work two to three jobs to take care of their family is a common story in America, especially with middle class America.”

Larson called out the two establishment figures at the top of his campaign: the chair is Daniel Papermaster, a lawyer and former aide to two former senators, Chris Dodd and Joseph Lieberman; and the finance chair is Alan Lazowski, a wealthy philanthropist and chief executive of Laz Parking.

Lazowski was a key supporter of Bronin’s in Hartford.

“But John has been a dear friend for over 40 years, and he’s always delivered for our district, for all 27 towns, for Hartford,” Lazowski said. “And I believe that he’s the right leader we need to get things done. His seniority in Congress is unparalleled, and you can’t just come in as a freshman and have an impact.”

Lazowski said he tried to talk Bronin out of running, and he dismissed concerns about Larson’s age. His father, Rabbi Phillip Lazowski, is 95 and working on his 16th book.

“He works harder than anyone I know, and John has that spirit,” Lazowski said.

Joe Toner, the executive director of the Connecticut Building Trades Council, which represents 30,000 union construction workers, said the council already has endorsed Larson, an old friend.

“He’s been by our side for the last 27 years, 28 years, and that’s not going to change. He’s never been a bad vote for us in the building trades. Quite frankly, he’s never been a bad vote for the district,” Toner said. “So we’re honored to support him. We’re going to stick with him. This is no time to make a change.”

Ruth Fortune, 37, a Hartford school board member, filed campaign papers July 3 and was quickly followed by Councilman Jack Perry, 35, of Southington. By the end of August, the field included Bronin, 46, and the 43-year-old Gilchrest.

On Friday, Bronin said Larson’s announcement was evidence that time has passed him by. Pledging action in 100 days on an agenda he cannot deliver was wrongheaded, Bronin said.

“While I have an enormous amount of respect for John Larson, I don’t think John Larson recognizes the moment that we’re in,” Bronin said. “Voters don’t want empty promises. They don’t want to be misled. Voters want to see that we recognize that if we’re going to deliver the things that our country needs, we have to build a different kind of political movement.”

Bronin waited to talk to reporters at a riverside park in East Hartford after Larson’s event. Gilchrest offered a similar critique in an emailed statement, expressing admiration and a demand for a change.

“I’m not running for Congress as a referendum on John Larson — I’m running because Congress as a whole isn’t listening to the voices of everyday people and has failed to deliver the change families need,” she said. “We can’t keep expecting the same people to do better next time.”

“Our families deserve a representative who will meet this moment with urgency and deliver real solutions — as I’ve done here in Connecticut on paid leave, gun safety and reproductive freedom. We can’t wait any longer.”

Larson left the union hall for a fundraising lunch at Cafe Aura, the Manchester restaurant owned by Geno Auriemma. Larson reported having less than $300,000 in his campaign account as of June 30. Bronin reported raising $500,000 in his first week.

The next campaign finance reporting period is in October.