Seth Moulton Told NBC Socialists Belong in His Party and Instantly Regretted it

Seth Moulton sat down on NBC the morning of his Massachusetts primary and told America the Democratic Socialists of America belong in his party.

AOC had already picked a different Democrat to prove him right.

By the time polls closed, the socialists he welcomed had delivered their answer.

What the Marine Told NBC Before He Lost

Rep. Seth Moulton sat down on NBC's Meet the Press NOW on September 1 – the same day as his Massachusetts primary – and told a national audience the Democratic Socialists of America deserve a seat in the Democratic tent.

"Yes. Look, they are speaking to the needs of their communities," Moulton said. "If we want to be a majority party, we've got to have the majority points of view."

He went further, arguing the media blows the differences between DSA members and mainstream Democrats out of proportion.

Rep. Jared Moskowitz of Florida had just drawn the opposite line on the same program – saying Democratic Socialists "can't coexist with me" inside the Democratic Party.

Moulton went the other direction.

And then he lost the primary to the candidate the socialists were already backing.

AOC had endorsed Ed Markey twelve days earlier.

She picked her side on August 20 – the clearest possible signal that the left wasn't waiting for Moulton's invitation.

The DSA wasn't undecided.

They had their candidate, and it wasn't Moulton.

What the DSA Actually Is and Who They Actually Backed

The Democratic Socialists of America is not the progressive wing of the Democratic Party.

It is a separate political organization with a platform that includes abolishing ICE, implementing Medicare for All as a non-negotiable demand, and opposing American military assistance to Israel.

DSA members have openly refused to condemn Hamas.

The organization ran candidates in Democratic primaries in 2026 explicitly targeting pro-Israel incumbents – the same ideological allies Moulton spent his career defending.

These are not fringe disagreements.

Their most prominent national voice – AOC – spent the final weeks of the Massachusetts primary telling voters to support the man running against Moulton.

Moulton told NBC the media overstates how different the DSA's vision is from mainstream Democrats.

The Massachusetts electorate delivered its verdict on that claim the same afternoon.

The Big Tent Swallowed Him

Democrats reach for the same answer every time they lose.

Losing suburbs? The tent needs to be bigger. Losing the base? Bigger still.

The logic sounds reasonable until you try to build the coalition.

Moulton ran for Senate as the moderate who could expand it – credible on national security, acceptable to the left, palatable to the center.

He tried to appeal to swing voters by being the serious veteran.

He tried to appeal to the left by welcoming its most radical members into his tent.

He ended up with neither.

Markey – an 80-year-old incumbent whose most prominent endorser campaigns to abolish the fossil fuel industry – beat him easily.

Moskowitz understood the math.

He drew the line and told national television that Democratic Socialists cannot coexist with him in the same party.

That is a position a working-class voter in a competitive district can understand.

Moulton's position – that the Marine who wants to rebuild the Navy and the activist who wants to abolish ICE are the same kind of Democrat – is not.

Every Republican in a competitive race just watched a Senate candidate make that argument and then lose to the candidate the socialists actually supported.

What Massachusetts Just Told Every Moderate Democrat

Moulton tried something specific: run as the reasonable alternative while simultaneously embracing the faction the party cannot fully defend in a general election.

It didn't work.

The man backed by AOC and the organized left won easily.

His big tent welcome didn't win him socialist votes – it handed Republicans an attack ad and cost him his credibility as a moderate.

He offered the DSA a seat at his table.

They were already seated at Markey's.

Every Democrat eyeing a similar strategy in 2026 just watched what Massachusetts said about it.

The tent doesn't grow toward the center by opening wider on the left.

It just gets more crowded in one direction – and leaves the moderate who invited everyone with nowhere to stand.

Sources:

• "Moulton: There's Room for DSA in Democratic Party, Media Overblow Differences Between Them, Other Dems," Breitbart, September 1, 2026.
• "AOC Endorses Sen Ed Markey as Incumbent Faces Dem US Senate Primary Challenge from Rep. Seth Moulton," Fox News, August 21, 2026.
• "Ed Markey Defeats Seth Moulton in Massachusetts Democratic Senate Primary," The Hill, September 1, 2026.
• "Socialist Insurgency Heads to Trump's Backyard, Targets Pro-Israel Democrat," Fox News, 2026.