Rep. Stephen Lynch first arrived in Washington, D.C. during the administration of George W. Bush. In that era, Lynch, a self-described moderate from South Boston, may not have stood out, but said he's concerned about today's Democratic Party is moving too far from the center.

“I’m a moderate, so I do worry about it. In some cases, we’re running away from the electorate with some of our issues,” Lynch said during an interview with Boston Public Radio Wednesday.

Lynch has been a solidly reliable Democratic vote throughout his career, according to the website GovTrack, but in a changing era, he’s beginning to find himself out of place. Rep. Katherine Clark, his colleague in the Massachusetts delegation and vice chair of the House Democratic Caucus, has come out in support of Medicare for All. In February, Rep. Joe Kennedy III also threw his support behind the bill. With 118 sponsors, the bill now has the majority of the Democratic caucus behind it, leaving Lynch in the minority of his own party.

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Lynch, however, insists endorsing ideas like Medicare for All and the Green New Deal will scare away older voters who will be frightened by the party’s leftward tilt.

“I think it scares a lot of seniors,” Lynch said. “You know, they hear that they’ve paid into Medicare all their lives, and now if we’re going to expand that pool of money to cover the entire population, they’re worried about that.”

Lynch said that he believes the concept of the Green New Deal, while noble, is unrealistic. He said he believes that it will more likely take 40 to 50 years to move the nation’s energy grid to one that is completely free of fossil fuels — not 10, as the resolution hopes to achieve.

“Great idea, good for the environment, but we need a bridge from where we currently are to where we want to be,” Lynch said. “I agree with the place we want to get to, it’s just the details on how we get there that’s the real [problem].”

Lynch has endorsed former Vice President Joe Biden's presidential bid — in fact, he enthusiastically threw his support behind Biden even before he officially jumped in the race. Much of Lynch’s calculus is predicated on Biden having a stronger understanding of the electorate than candidates like Sens. Bernie Sanders and Elizabeth Warren. During Wednesday’s interview, Lynch said that he’s been uncomfortable with ideas that have a “socialist bent” — like tuition free college, a universal basic income and free health care — that he’s seen debated in the race.

More than the policies, however, Lynch is concerned that Sanders’ identification as a socialist may win the support of millennials, but will terrify older citizens who came of age during the Cold War.

“I think the talk of going socialist, I think most people 50 years and older probably have a different view of socialism and whether or not that’s good for our country,” Lynch said. “I understand that for millennials they have a different view of it, but I think for the moderates, I think that frightens them.”

In March, Lynch will have to fend off a challenger who is seemingly running to his left: video game developer Brianna Wu. Unlike Lynch, she has embraced Medicare for All, free public college and the Green New Deal. Wu lost her first primary challenge to Lynch in 2018, winning less than 30 percent of the vote. A presidential election, however, may galvanize more voters to come out during the primaries. Secretary of the Commonwealth Bill Galvin told WGBH News in April that he is anticipating a massive turnout in both the primaries and the general election.

While it is too early to tell if Lynch’s centrism will cost him his seat, the party is clearly changing. In June, New York Times reporter Astead Herndon asked Biden if he considers himself a moderate. Biden refused to classify himself as such.

“No. No, I wish they called me that every time I ran and won in Delaware, I would’ve won 80 percent of the vote,” Biden said. “Look at my record, man.”