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The primary pitting an 80-year-old progressive against an insurgent the left loathes

Sen. Ed Markey wants another term. Rep. Seth Moulton is taking him on. What does the Democratic base care about more?

The prototypical Democrat vulnerable to a primary this year has been old, in Washington a long time, and vulnerable from the left.

But in Massachusetts, there’s a race that’s scrambling that formula. Sen. Ed Markey is 80, and he’s been in Congress for 50 years. But he’s been a stalwart ally of progressives; he was, for instance, the main Senate champion of the “Green New Deal.” And the leaders of the Democrats’ left flank, like Sens. Bernie Sanders and Elizabeth Warren, are swinging into action to try and defend him. “It’s not your age, it’s the age of your ideas. And in this race, I’m the youngest guy,” Markey has said.

His opponent, Seth Moulton, a 47-year-old Marine Corps veteran, also goes against type. While “moderate” and “establishment” often are treated as synonyms, Moulton has a history of pushing back against both progressive activists and older Democratic leaders. In his current run, he’s made generational change his main issue, including some blunt warnings about Markey’s age.

“If Democrats win the Senate, it will almost certainly be by one vote, and we can’t afford to lose that vote due to a medical absence or emergency,” Moulton told me in an interview. “That’s not ageism, that’s just actuarial tables.”

In the primary where Sen. Ed Markey is being challenged by Rep. Seth Moulton, Markey is championing his progressive credentials, but Moulton is running as the candidate of generational change.

This differs from other hotly contested primaries in that Democrats’ left faction is rallying to keep 80-year-old Markey in power for another term, while the less solidly progressive Moulton is taking on Democratic leaders.

The outcome will reveal whether Democratic primary voters are more fired up about progressive ideology, or whether they’re ready to toss out older incumbents of any ideological stripe.

But his Senate campaign isn’t the first time he’s taken on Democratic leaders. In 2018, he led a (failed) effort to stop Nancy Pelosi from becoming speaker again, arguing again that the aging House leadership needed to clear a path for younger members. In 2024, he became one of the first prominent Democrats to bail on President Joe Biden after his disastrous debate, saying the president needed to “let new leaders rise up.”

The party establishment, Moulton told me, has “failed to be honest with the American people about the challenges we face.” He cited Democrats denying there was “an immigration problem at the southern border under Biden,” their insistence that Biden-era inflation was “transitory,” and their initial defense of Biden after the debate exposed his frailty.

Some of his criticisms of the party have rankled progressives. After President Donald........

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