NYC's Political Earthquake: Mayor Mamdani's Progressive Slate Sweeps Congressional Primaries, Ousting Two Democratic Incumbents

What Happened? A Quick Breakdown

Three congressional races. Three Mamdani endorsees. Three wins.

Here's the scorecard:

• NY-10 (Lower Manhattan & Brooklyn): Former City Comptroller Brad Lander defeated two-term incumbent Rep. Dan Goldman, capturing a commanding two-thirds of the vote.
• NY-13 (Upper Manhattan & parts of the Bronx): Community organizer and democratic socialist Darializa Avila Chevalier, 32, edged out five-term incumbent Rep. Adriano Espaillat in a nail-biting finish.
• NY-7 (Brooklyn & Queens): State Assemblymember Claire Valdez, 36, won the open-seat race to succeed retiring Rep. Nydia Velázquez, defeating Brooklyn Borough President Antonio Reynoso.

All three districts are considered solidly Democratic, meaning Tuesday's primary victories are, for all practical purposes, a near-guarantee of seats in Congress come November.

The Man at the Center: Who Is Zohran Mamdani?

If you haven't been following New York City politics closely, here's what you need to know: Zohran Mamdani is the city's newly elected mayor, a democratic socialist who pulled off a history-making victory in November 2025, defeating former Governor Andrew Cuomo — a titan of the Democratic establishment. Now, less than a year into his term, he's proven he isn't just a mayor. He's a political movement.

Mamdani didn't just throw his name behind these candidates and call it a day. He showed up. He rallied alongside them at watch parties and rallies. He mobilized an army of campaign volunteers to knock on doors. He even posted TikToks. His team came armed with the same grassroots energy that swept him into City Hall — and it worked again.

"Mayor Mamdani is incredibly popular and he has proven that he can harness that popularity," his press secretary Joe Calvello wrote on social media after the results came in. "It's time for the political class to understand that and be on the right side of it or be bound to the dustbin of history."

Race by Race: The Stories Behind the Numbers

Brad Lander vs. Dan Goldman (NY-10): The Definitive Blowout

The first race to be called Tuesday night was perhaps the least surprising — but no less significant. Brad Lander, 56, the former New York City Comptroller, had led polls for months against incumbent Rep. Dan Goldman, the former federal prosecutor best known for leading Democrats' first impeachment proceedings against President Trump in 2019.

Lander won with roughly 65% of the vote — a decisive margin that spoke volumes about the priorities of this Lower Manhattan and Brooklyn district.

The central battleground? Israel and Gaza. Goldman, who is Jewish, held support from both AIPAC and the more moderate J Street, and worked to frame himself as a progressive who could support Israel while criticizing Prime Minister Netanyahu. Lander, also Jewish, took a harder line, calling Israel's conduct in Gaza a "genocide" and promising to co-sponsor legislation restricting U.S. military aid.

Lander also framed Goldman as a "corporate Democrat" out of step with working New Yorkers. He brought heavyweight progressive firepower to the race, earning endorsements from Senators Bernie Sanders and Elizabeth Warren alongside Mamdani's blessing.

Goldman, for his part, had the establishment squarely in his corner. Governor Kathy Hochul backed him. So did House Minority Leader Hakeem Jeffries, who represents a neighboring Brooklyn district. It wasn't enough.

"What a glorious time to be a New Yorker," Lander told a packed watch party in Gowanus on election night.

Darializa Avila Chevalier vs. Adriano Espaillat (NY-13): The Night's Biggest Upset

If Lander's win was expected, what happened in New York's 13th District was the genuine earthquake of primary night.

Darializa Avila Chevalier — a 32-year-old community organizer, DSA member, and self-described democratic socialist — defeated five-term incumbent Rep. Adriano Espaillat, the 71-year-old Chairman of the Congressional Hispanic Caucus and the first Dominican-American ever elected to Congress. Espaillat had a who's-who of Democratic establishment figures in his corner: House Minority Leader Hakeem Jeffries, and a broad coalition of Latino political leaders.

Chevalier's campaign was a true underdog story. Her bid flew largely under the radar until Mamdani endorsed her in the closing weeks, bringing his volunteer army and star power into the fold. She campaigned hard on affordable housing, immigrant rights, and expanding the social safety net — and she charged that Espaillat had grown out of touch with the working-class constituents in Harlem, Washington Heights, and the Bronx.

The race also turned bitter toward the end, with Espaillat's camp zeroing in on controversial past social media posts by Chevalier, including one in which she used colorful language to criticize Democratic leaders. It didn't stick with enough voters.

"Tonight wasn't our night, but I love you anyway," Espaillat said in a gracious concession speech.

Chevalier is now all but certain to become a member of Congress in January.

Claire Valdez vs. Antonio Reynoso (NY-7): A Progressive Civil War — And a Clear Winner

The 7th District race was the most internally complicated of the three. This wasn't progressives vs. the establishment — it was progressives vs. progressives.

The open seat, vacated by the retirement of legendary Rep. Nydia Velázquez (who first took office in 1993 and is a towering figure in New York's Hispanic community), attracted a field including Brooklyn Borough President Antonio Reynoso, himself a progressive with genuine community ties. The difference? Velázquez backed Reynoso. Mamdani backed Valdez.

Claire Valdez, 36, a first-term state Assemblymember who moved to the city in 2015, ran on a platform of "Medicare for All," a public housing option, and a sharper stance against Israel's conduct in Gaza. She won decisively.

"Tonight, we haven't just won an election," Valdez told supporters. "We have declared that this movement is durable, that it is growing, and that it will not stop until working people are no longer asked to just build the table, no longer just offered a seat at the table, but will run the table."

Reynoso conceded gracefully, pledging to continue supporting Mamdani's agenda.

What Does This Mean for the Democratic Party?

Bluntly? Quite a lot.

These three districts are among the most rapidly gentrifying in New York City, and notably, they are also where Mamdani performed strongest during his own mayoral campaign. The results suggest that the coalition that elected him — young voters, immigrants, renters, progressive professionals — is not just loyal to him personally. It is a transferable political force.

The polling data backs up the appetite for this kind of politics. According to a poll highlighted by CNN, the Democratic Socialists of America have a higher net favorability among Democratic voters than Congressional Democrats by 13 points. Gallup polling from September 2025 found that 66% of Democrats — up from 50% in 2010 — view socialism more favorably than capitalism.

That's a remarkable shift, and Tuesday's results appear to be its most concrete political expression yet.

For Mamdani, the night reinforced what his mayoral victory first suggested: he has something larger than a single campaign in mind. His endorsements came packaged with prime seating next to him at Knicks watch parties, an army of canvassers, and a sophisticated social media presence. Like few politicians in recent memory, he is building a durable, loyal, multi-issue movement — and the Democratic Party's establishment is going to have to grapple with that.

The Republican Reaction: "Americans Should Be Terrified"

Republicans were quick to frame the night as a warning sign — and a gift.

"Tuesday was the night the Democrat establishment officially surrendered to Zohran Mamdani and the socialist wing of their party," said National Republican Congressional Committee spokesperson Mike Marinella. "Every House Democrat, in safe and competitive districts alike, will now answer to the radicals calling the shots. And Americans should be terrified by where the Democrat Party is headed."

Whether that framing works in November — particularly in the competitive suburban districts that will decide House control — remains to be seen. But for Republicans heading into the midterms, a New York City full of DSA-backed congressmembers is a fundraising message and a campaign ad waiting to happen.

The Bigger Picture: A Movement, Not Just a Moment

What happened in New York City on Tuesday night didn't come out of nowhere. It's part of a broader pattern of progressive primary challenges gaining ground across the country — from state legislatures to school boards to now Congress.

What makes New York different is the institutional muscle behind it. Mayor Mamdani has city government, a grassroots army, deep name recognition, and the kind of personal popularity that translates into endorsement power. His model — elect progressives at every level, build coalitions around affordability and economic justice, and use institutional power to push further left — is now a proven playbook.

The questions that now hang over the Democratic Party are not small ones: Can the establishment adapt? Will the new progressive delegation work constructively with moderates to flip the House? And is what's happening in New York City a preview of what's coming to the rest of America?

For now, in the five boroughs at least, the left is celebrating. And they've earned it.

Key Takeaways at a Glance

• Three for three: All Mamdani-endorsed congressional candidates won their Democratic primaries.
• Two incumbents ousted: Rep. Dan Goldman (NY-10) and Rep. Adriano Espaillat (NY-13) both lost.
• Establishment on the defensive: House Minority Leader Hakeem Jeffries backed losing candidates in multiple races.
• DSA gains power: Chevalier and Valdez are both DSA members; their wins expand the socialist wing in Congress.
• November looks favorable: All three districts are heavily Democratic, making general election wins likely.
• Mamdani's influence confirmed: Less than a year into his mayoral term, he is a major force reshaping Democratic politics.