Zohran Mamdani’s growing influence over the Democratic Party was on show in New York City on Tuesday as three congressional candidates endorsed by New York’s democratic socialist mayor won closely watched primaries, while voters in Maryland, Utah and South Carolina cast ballots in primaries and run-offs.Brad Lander, the former New York City comptroller who also ran for mayor last year before endorsing Mamdani, won his race comfortably, defeating the Democratic representative Dan Goldman.Another Mamdani ally, Claire Valdez, a state lawmaker and former union organiser, defeated Antonio Reynoso, the preferred successor of retiring Democratic Representative Nydia Velázquez in New York’s seventh district, encompassing parts of Brooklyn and Queens. And in a stunning upset, the public defence investigator Darializa Avila Chevalier toppled Representative Adriano Espaillat, the powerful five-term incumbent who chairs the Congressional Hispanic caucus, in the state’s diverse 13th congressional district, which covers Upper Manhattan and parts of the Bronx.“What a glorious time to be a New Yorker,” Lander declared at this election night party in Brooklyn, where he was joined by the mayor. Mamdani then appeared at a watch party for Valdez, where he told a jubilant crowd: “The old politics that got us into this crisis is not the politics that’s going to get us out of this crisis.”It was a clean sweep for Mamdani, who waded into the House primaries earlier this year, spending his political capital to boost three leftwing allies – a gamble that would test his popularity and his influence. With his slate of candidates all but certain to be elected to Congress in November, Mamdani has left his stamp on the state’s congressional delegation and expanded his ascendant progressive movement.New York City mayor Zohran Mamdani takes a picture with supporters after a campaign event for Claire Valdez in New York. Photograph: Ryan Murphy/The New York Times