New York City Mayor Zohran Mamdani scored a major political victory Tuesday night after three congressional candidates he endorsed won closely watched Democratic primaries across the city.
The results showed Mamdani’s growing influence inside the Democratic Party and gave momentum to the party’s left flank as voters in New York, Maryland, Utah and South Carolina cast ballots in primaries and runoff elections.
In New York’s 10th Congressional District, former New York City Comptroller Brad Lander defeated Rep. Dan Goldman, a high-profile incumbent who had support from several establishment Democrats. Lander, who ran for mayor last year before later backing Mamdani, framed his campaign around affordability, progressive priorities and a call for new leadership.
In New York’s 7th District, state lawmaker and former union organizer Claire Valdez defeated Brooklyn Borough President Antonio Reynoso. Reynoso had been backed by retiring Rep. Nydia Velázquez, who currently holds the seat. Valdez’s win marked another victory for Mamdani-aligned progressives in a district covering parts of Brooklyn and Queens.
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The biggest upset came in New York’s 13th District, where public defense investigator Darializa Avila Chevalier defeated Rep. Adriano Espaillat, a five-term incumbent and chair of the Congressional Hispanic Caucus. The district includes Upper Manhattan and parts of the Bronx. Avila Chevalier had argued that the district needed younger, more working-class-focused representation, while Espaillat emphasized his experience and record on immigration and civil rights.
Together, the three victories gave Mamdani a clean sweep. The mayor had taken a political risk by backing challengers against powerful Democrats and establishment-supported candidates. Instead, the results strengthened his image as a rising power broker in New York politics.
Speaking at election night events, Mamdani and his allies framed the wins as proof that voters want a different direction from the Democratic Party. The results could also shape New York’s congressional delegation for years, since all three districts are strongly Democratic and the primary winners are expected to be favored in November.
Elsewhere in Manhattan, Jack Schlossberg, the grandson of former President John F. Kennedy, failed to win the Democratic primary to replace retiring Rep. Jerry Nadler in New York’s 12th District. The race had drawn national attention because of Schlossberg’s famous political name and large social media following.
Micah Lasher, a longtime New York political figure, won the primary in the deep-blue district. The crowded race also included anti-Trump commentator George Conway and state Assemblymember Alex Bores, whose campaign became tied to debate over artificial intelligence regulation and spending from tech-linked groups.
President Donald Trump reacted to the New York results on social media, celebrating the losses of Goldman and Conway. Goldman had previously served as lead counsel to House Democrats during Trump’s first impeachment, making his defeat especially notable for the president’s supporters.
While the night highlighted progressive gains in New York City, more moderate Democrats also held ground in key swing areas. On Long Island, Democratic Reps. Tom Suozzi and Laura Gillen defeated primary challengers as they prepare to defend competitive seats in November.
In the Hudson Valley, Cait Conley, a former White House counterterrorism official and Army combat veteran, won the Democratic primary to challenge Republican Rep. Mike Lawler in New York’s 17th District. That race is expected to be one of the most important House contests in the country, as Democrats try to win back control of the chamber.
Republicans also saw Trump’s influence hold in upstate New York, where Trump-backed Anthony Constantino won the GOP primary for the seat being vacated by Rep. Elise Stefanik.
Outside New York, Maryland voters selected Adrian Boafo in the primary to replace retiring longtime Democratic Rep. Steny Hoyer. In Utah, former Rep. Brad McAdams won a Democratic primary in a newly drawn Salt Lake City-area district. In South Carolina, state Attorney General Alan Wilson won the Republican runoff for governor after Trump made the unusual move of endorsing both candidates in the race.
Why It Matters
The results show that Mamdani’s political movement is no longer limited to City Hall. His endorsed candidates defeated incumbents and establishment-backed figures, signaling that New York’s progressive wing can shape congressional races. At the same time, moderate Democrats remain focused on swing districts that could decide control of the House in November.
What Comes Next
The Mamdani-backed winners are expected to be strong favorites in November because their districts are safely Democratic. National attention will now shift to competitive House races, including New York’s 17th District, where Democrats hope to defeat Rep. Mike Lawler and move closer to reclaiming the House majority.
A televised results segment showed Mamdani-backed candidates winning key New York Democratic primaries, strengthening the mayor’s influence in the party.
BREAKING: All mayor Mamdani-backed candidates win New York primaries in clean sweep, CNN projects pic.twitter.com/zMA9Sciure
— Insider Paper (@TheInsiderPaper) June 24, 2026
