Mamdani-backed leftists score primary upsets, reshaping New York Democrats

Zohran Mamdani’s endorsements helped three left-leaning Democrats sweep New York congressional primaries on June 23, 2026, with former New York City Comptroller Brad Lander defeating Rep. Dan Goldman in the 10th District, Darializa Avila Chevalier beating Rep. Adriano Espaillat in the 13th District, and state Assemblymember Claire Valdez winning in the 7th District. The clean sweep gave the New York City mayor an immediate test case for how far his brand of politics can travel inside a party still trying to define itself.

The three congressional winners are expected to prevail in November in heavily Democratic districts, which makes the bigger fight internal rather than general-election based. Their victories replaced two incumbent Democrats with challengers to their left on Israel and immigration, issues that have increasingly split the party’s urban base from its national leadership. If Democrats win back the House, House Democratic Leader Hakeem Jeffries could be managing a caucus with a stronger left flank and less room for centrists to shape the agenda.

The leftward shift was not limited to the congressional map. Mamdani-backed candidates also won five state-office races, and the Democratic Socialists of America said its organizers knocked on more than 700,000 doors to help power the slate. Those results could raise the number of democratic socialists in Albany from nine to as many as 16, a change that would give the movement a much larger foothold in state politics.

Republicans quickly seized on the outcome to argue that Democrats have been overtaken by socialism, while one election analyst called the result an earthquake. The scale of the victories gave Mamdani a new measure of influence, and underscored how his political style has become a live issue for Democrats weighing whether a more explicitly progressive message expands their coalition or deepens their fractures.

The primaries landed on a June 23 election day that also included contests in Maryland, Utah and South Carolina, placing New York’s left-versus-establishment fight in a broader national frame. For Democrats looking ahead to the midterms, the question is no longer whether Mamdani’s allies can win in New York City politics, but whether they can carry that model into swing districts and statewide races beyond it.