Mamdani-Backed Progressive Slate Sweeps New York Democratic Primaries

In a significant show of force for New York's progressive wing, candidates endorsed by Mayor Zohran Mamdani dominated the state's Democratic congressional primaries on Tuesday, June 23, 2026, with victories that signal a major realignment within the party. Brad Lander, the former New York City comptroller, defeated incumbent Representative Dan Goldman in the 10th District with 65.8% of the vote. Claire Valdez, a state assemblywoman and former union organizer, won the 7th District primary with 56.1%, surpassing Antonio Reynoso, who had been backed by retiring Representative Nydia Velázquez and state Attorney General Letitia James. Most strikingly, Darializa Avila Chevalier, a public defense investigator, upset five-term incumbent Representative Adriano Espaillat in the 13th District, capturing 49.4% of the vote to Espaillat's 45.9%, an outcome that stunned observers given Espaillat's seniority and role as chair of the Congressional Hispanic Caucus.

The clean sweep reflects Mamdani's expanding influence within Democratic politics and his ability to mobilize voters around a progressive agenda focused on economic justice and systemic reform. All three winning candidates are expected to secure their House seats in November, given the Democratic-leaning nature of their districts. Mamdani appeared at celebration events for multiple winners on election night, declaring to supporters that "the old politics that got us into this crisis is not the politics that's going to get us out of this crisis." The victories will likely add three allies to the Democratic congressional delegation and send a pointed message to establishment figures in Washington, including House Democratic Leader Hakeem Jeffries, who had campaigned against Mamdani's slate.

Elsewhere on the ballot, Jack Schlossberg, the 33-year-old grandson of President John F. Kennedy, failed in his bid to revive his family's political legacy in the 12th District race following Representative Jerry Nadler's retirement. Micah Lasher, a longtime New York politician, won that crowded primary with 39.1% of the vote in what became one of the nation's most expensive congressional primaries, attracting millions in spending from former Mayor Michael Bloomberg and other major donors. The race generated national attention over AI-related issues, with candidate Alex Bores criticizing billionaire involvement in the contest.

In other statewide races, incumbent Comptroller Thomas P. DiNapoli easily fended off progressive challengers Drew Warshaw and Raj Goyle in his primary, winning 65.2% of the vote despite facing his first serious primary challenge in his long tenure overseeing the state's financial oversight office. On Long Island, Democratic freshmen Representatives Tom Suozzi and Laura Gillen readily defeated primary challengers to secure their nominations for competitive swing seats in November. In the Hudson Valley's 17th District, Cait Conley, a former White House counter-terrorism official and army combat veteran, won a competitive Democratic primary and is positioned to take on Republican Representative Mike Lawler in a closely watched general election race.

The results underscore a widening divide within New York's Democratic Party between its progressive and moderate wings, with Mamdani's movement demonstrating particular strength in urban congressional districts while establishment-aligned Democrats retained influence in other races. The victories provide the democratic socialist mayor with leverage to reshape both the state delegation and national Democratic politics heading into the general election campaign.