Rep. Seth Moulton (D–Mass.) announced on Oct. 15, 2025, that he will run for Senate instead of seeking re-election to the House.
According to Kelly Garrity of Politico, “Moulton will challenge Sen. Ed Markey for his Senate seat in 2026, setting up one of the biggest tests of Democratic voters’ appetite for generational change following the 2024 presidential election.”
With his entry, the congressman positions himself in a moment when generational change is pushing onto center stage in Massachusetts politics, opposite a well-entrenched incumbent.
As of Oct. 14, 2025, several independent forecasters rate the general election for this seat as strongly favorable to Democrats: The Cook Political Report and Inside Elections label it “Solid Democratic,” while Sabato’s Crystal Ball rates it “Safe Democratic.”
In other words, the hardest-fought contest may unfold earlier—within the Democratic Party primary.
In his campaign announcement, Moulton framed his decision in stark terms: “Real people across Massachusetts are being hurt by Democratic leaders refusing to do everything they can to win. We’ve got to look in the mirror and be honest. It’s time for change.”
Moulton’s critique signals a broader strategy: pressuring his party to adopt a more aggressive approach as key congressional races loom.
A former Marine officer, Moulton first emerged in 2014 with a notable Democratic primary win, defeating incumbent John Tierney with 50.8% of the vote (to 40.1%). In the general election, he then defeated Republican Richard Tisei, with 53.6% of the vote to 40.2%.
His hold on the district strengthened over subsequent cycles: he was re-elected in 2018 (+34 points), 2020 (+31 points), and 2022 (+28 points); and was unopposed in 2016 and 2024, according to Ballotpedia.
The ratings also underscore favorable terrain: as of Oct. 14, 2025, the 6th District is likewise rated “Solid Democratic” by Cook and Inside Elections and “Safe” by Sabato’s Crystal Ball. That cushion likely eased Moulton’s leap to a Senate primary, even as it opens a succession contest for his House seat in a Democratic stronghold.
The anticipated face-off with Ed Markey plays into a national moment where calls for generational renewal collide with arguments for programmatic continuity. The incumbent senator—an influential progressive and co-author of landmark climate proposals—has a well-tested political base. Moulton’s bid, by contrast, emphasizes electoral performance and leadership style more than sharp ideological breaks; the core message—“It’s time for change”—targets the capacity to win and expand the Democratic coalition.
As of Oct. 15, 2025, thirty-nine members of Congress—eight senators and thirty-one representatives—had announced they would not seek re-election to their current seats in 2026, according to Ballotpedia News. This wave—retirements, bids for other offices, and career resets—reshapes internal balances and local ambitions, while multiplying open primaries in the months ahead.
By the newsroom — Sources: Ballotpedia News (Briana Ryan, Oct. 16, 2025)
