Mamdani-backed progressives score key primary wins, rattle Democratic establishment

Mamdani-backed progressives won three Democratic congressional primaries in New York, giving Zohran Mamdani a likely trio of allies in Congress and a direct setback for House Democratic Leader Hakeem Jeffries. The contests, held June 23 in New York, became a test of whether Mamdani’s 2025 rise could translate into a broader progressive bench inside the Democratic Party.

Former New York City Comptroller Brad Lander defeated Democratic Rep. Dan Goldman in New York’s 10th Congressional District, the first win for the Mamdani-backed slate. NBC News reported that Lander captured about two-thirds of the vote. In the open 7th District, state Assembly member Claire Valdez won the Democratic nomination to succeed retiring Rep. Nydia Velázquez. Darializa Avila Chevalier then defeated 10-year incumbent Rep. Adriano Espaillat, who chairs the Congressional Hispanic Caucus.

The three races sharpened a fight over the party’s direction, especially on Israel’s war in Gaza and how strongly Democrats should criticize Israel. Mamdani and his allies pushed to move the party further left on those questions, while establishment Democrats warned that sharper rhetoric could cost them swing voters in the 2026 midterms. Jeffries had campaigned aggressively against Mamdani’s candidates and lost, even after brushing off the primaries before polls closed and saying a handful of races in one state or two would not reshape House Democrats.

Mamdani cast the results as a challenge to the party’s center of gravity and the political class that has dominated it. He said the point was “electing better Democrats” and putting working people back at the heart of politics. The victories will likely give the New York mayor three new allies in Congress, expanding his reach beyond City Hall and into the next fight over who gets to define the Democratic Party’s candidate pipeline heading into the next congressional cycle.