Mamdani-Backed Insurgents Upset Incumbents in New York Primaries

On June 23-24, 2026, three candidates endorsed by New York City Mayor Zohran Mamdani won Democratic primaries for U.S. House seats. Brad Lander defeated incumbent Rep. Dan Goldman in the 10th District, Darializa Avila Chevalier unseated Rep. Adriano Espaillat in the 13th District, and Claire Valdez captured an open seat previously held by Rep. Nydia Velázquez. The victories marked the first time Mamdani’s slate overcame established incumbents in congressional races.

The Independent

Mamdani, a Democratic socialist who beat former Governor Andrew Cuomo in the 2025 mayoral primary, has built a coalition around affordability, anti-war, and anti-Israel positions. His endorsements followed a year of cultivating “a new power broker” status in New York politics, prompting both progressive and establishment factions to view the primaries as a test of the Democratic Party’s direction.

Fox News (website)

• Zohran Mamdani – Mayor, Democratic socialist.

Newsweek

• Letitia James – New York Attorney General, former Trump-fraud prosecutor.

CNN

• Hakeem Jeffries – House Minority Leader, New York.

The Independent

• Chuck Schumer – Senate Majority Leader, New York.

New York Post

• Josh Gottheimer, Greg Meeks, Vicente Gonzalez – Moderate Democratic congressmen.

New York Post

• Morris Katz – Campaign strategist allied with Mamdani.

CNN

• Darializa Avila Chevalier, Brad Lander, Claire Valdez – Mamdani-backed candidates.

CNN

• Three Mamdani-endorsed candidates won, defeating two incumbents and securing one open seat.

CNN

• Fox News reported nine Democratic incumbents lost statewide, including seven state lawmakers and two congressmen.

New York Post

• Polls showed Avila Chevalier leading Espaillat 39 %-35 % (Data for Progress) and Lander leading Goldman 57 %-23 % (Emerson College).

Newsweek

Mamdani framed the results as “the beginning” of a broader demand for progressive policies. Jeffries emphasized a “working relationship” with Mamdani and downplayed any threat to House leadership, noting the need to focus on defeating Donald Trump. Schumer described the primaries as evidence of “tremendous energy” across the party and pledged to harness it for the 2026 elections. James warned that internal disputes should not “blow up” the party, likening destructive infighting to MAGA tactics.

Newsweek

James criticized Mamdani’s choices, saying the endorsed candidates “do not understand the politics of New York City” and lack experience with race and class issues. GOP strategists warned the wins could provide ammunition for attacks on Democrats in swing districts. Moderate Democrats such as Gottheimer and Meeks expressed concern that the socialist platform—particularly calls to abolish police and prisons—could jeopardize electoral prospects. Representative Gonzalez warned that the policies championed by the newcomers would be “very difficult” to sell in districts like South Texas.

CNN

The outcomes highlight a growing rift between the Democratic establishment and a progressive wing energized by affordability and anti-war messaging. Republicans may exploit the insurgents’ controversial positions in November, while Democratic leaders must balance coalition-building with maintaining appeal in moderate swing districts. The results also signal potential challenges for Jeffries’s bid to become Speaker if insurgent members demand policy concessions.

The Independent

Sources differ on the total number of incumbents defeated: Fox News cites nine statewide losses, while other outlets focus on the three congressional victories. Jeffries’s stance varies across reports—some portray him as dismissive of Mamdani’s influence, others note his “strongly disagree” position on specific races. Detailed voter-turnout data for younger demographics remain limited.

Newsweek

• “Some of the candidates that he has supported are individuals who do not understand the politics of New York City, the cultural differences from district to district, who have not been part of the history and the struggle of some of these districts, and are relatively new to the body politic,” — Letitia James, New York Attorney General

The Hill

• “We are showing that last June, a year ago tomorrow, was not an anomaly,” — Zohran Mamdani, New York City Mayor

CNN

• “No, Donald Trump has a working relationship with the mayor of the city of New York, and he’s made that publicly and explicitly clear to America, not once but twice in the Oval Office,” — Hakeem Jeffries, House Minority Leader

CNN

• “Many of us believe, as I do, that if you’re a socialist, you’re not a Democrat.” — Josh Gottheimer, Representative (NY)

CNN

• “I think that we spend a lot more time talking about labels than the average swing voter thinks about that,” — Morris Katz, campaign strategist

CNN

The three winners will face Republican challengers in the November general election, while Democrats nationwide assess how the insurgent victories will shape strategy for retaking the House and influencing the upcoming Speaker election. Party leaders are expected to negotiate policy priorities with the new progressive caucus to avoid fracturing the coalition ahead of the 2026 midterms.

CNN