Seth Moulton

Around 5 p.m. on primary day, I ran into Representative Seth Moulton at the polling station where I vote. When I asked if he would have changed anything about his campaign for US Senate if he could have done it over again, he said: “I’m sure there are things that I could have done differently along the way, but I’m very proud of the campaign that we’ve run, the team that we’ve built, and the values that we hold.”

It’s routine for candidates to say they are proud of their campaign. But I hope Moulton — who lost badly to Senator Ed Markey in the Democratic primary — does think about what he might have done differently. If he ever runs for office again — and I hope he does — he should do it in a way that’s truer to his own beliefs.

In the run against Markey, Moulton tried to make the fight strictly about age, while insisting there were no differences between himself and Markey on policy and ideology. Progressives were never going to buy that, especially with Markey making sure they would not forget that Moulton, as Markey put it, threw “trans kids under the bus.” But it was also no way to sell himself to voters who might actually have been looking for something different, not just for someone younger.

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As for Markey, at 80 he had grown very fond during the campaign of saying that it was not his age that matters, but his ideas.

In Tuesday’s primary, what seemed to matter most was the perceived progressiveness of those ideas versus those of the 47-year-old Moulton.

The Green New Deal, Medicare for All, civil rights for transgender athletes: By clinging to that ultra-progressive dogma, as well as to its disciples — Senators Bernie Sanders and Elizabeth Warren, Representatives Ayanna Pressley and Alexandria Ocasio-Cortez — Markey easily won. He will return to Washington for a sixth term, one that will take him to age 86, if he serves to the end of it.

Markey has said he would step aside if he felt he could not do the job. Would he also step aside to pave the way for a younger progressive protégé? That’s already a source of speculation and gossip.

For Moulton, taking on an entrenched incumbent like Markey was always going to be an uphill battle. But it was in character. After all, he won election to Congress in 2014 by ousting an incumbent Democrat, a somewhat rare feat in Massachusetts that endeared him to no one in the delegation.

Nothing he did afterwards, such as challenging the leadership of House Speaker Nancy Pelosi, made him any more popular with fellow lawmakers. He made things even harder for himself with the words he spoke about transgender athletes after the 2024 presidential election.

But he was right about the need to pass the torch.

And Markey was also right when it came to understanding that voters needed something more than age to convince them now was the time to do so.

Joan Vennochi is a Globe columnist. She can be reached at [email protected]. Follow her @joan_vennochi.