New York Mayor Zohran Mamdani scored a significant political victory on Tuesday as all three candidates he endorsed won their Democratic primary races, highlighting the growing influence of the party’s progressive wing in America’s largest city.
The most closely watched contest saw progressive candidate Brad Lander defeat incumbent Congressman Dan Goldman in New York’s 10th Congressional District. With most votes counted, Lander secured nearly 66 per cent of the vote compared with Goldman’s 34 per cent.
The race underscored deep divisions within the Democratic Party over the Israel-Gaza conflict. Lander has been sharply critical of Israel’s military actions in Gaza, while Goldman, a two-term congressman backed by pro-Israel groups, positioned himself as a strong supporter of Israel.
Mamdani celebrated Lander’s victory, praising his vision for a more progressive style of politics focused on working-class concerns.
Two other Mamdani-backed candidates also secured victories. Assemblywoman Claire Valdez defeated Brooklyn Borough President Antonio Reynoso in New York’s 7th District, while Darializa Avila Chevalier won the Democratic nomination in the 13th District.
Chevalier’s victory was particularly notable as she unseated longtime Congressman Adriano Espaillat, who had represented the district for five terms and currently serves as chair of the Congressional Hispanic Caucus. A doctoral student and activist, Chevalier gained attention for participating in pro-Palestinian demonstrations at Columbia University.
Mamdani described Chevalier as a candidate of “clarity, conscience and conviction” following her win.
The primary results are being viewed as an early test of Mamdani’s political influence since becoming mayor. His endorsements were aimed at boosting progressive candidates who support policies such as higher taxes on wealthy individuals, expanded social programs and major reforms to immigration enforcement.
All three winning candidates have publicly supported abolishing the U.S. Immigration and Customs Enforcement agency (ICE), increasing taxes on top earners and have accused Israel of committing genocide in Gaza, allegations that Israel strongly rejects.
The victories are likely to intensify debate within the Democratic Party about its future direction ahead of November’s midterm elections. Some establishment Democrats have warned that candidates aligned with the party’s left flank may struggle to attract moderate and swing voters in competitive districts.
Former U.S. President Donald Trump weighed in on the results, appearing to reference Mamdani’s growing influence in a social media post declaring that America would “never be a communist country.” Trump repeatedly labelled Mamdani a communist during the mayoral campaign, a characterization Mamdani has consistently rejected.
Following his victory, Lander said voters in Lower Manhattan and parts of Brooklyn had chosen leadership prepared to confront authoritarianism rather than compromise with it.
Goldman, meanwhile, accepted the outcome and congratulated his opponent, saying voters had made their decision. The congressman’s support for Israel had become a flashpoint during the campaign, drawing criticism from some progressive activists and businesses in his district.
Elsewhere in New York, political newcomer Jack Schlossberg, grandson of former U.S. President John F. Kennedy, was defeated in the Democratic primary for the 12th Congressional District. Schlossberg lost to Assemblymember Micah Lasher in a race to succeed retiring Congressman Jerry Nadler.
Conservative lawyer George Conway, a prominent critic of Trump and co-founder of the Lincoln Project, also failed to gain traction in the same district, capturing only a small share of the vote.
Despite the progressive victories, House Democratic Leader Hakeem Jeffries downplayed their broader significance, arguing that a handful of primary results would not fundamentally reshape the Democratic caucus in Congress.
For Mamdani, however, Tuesday’s results represent a clear endorsement of his effort to move New York Democrats further left and place working-class issues at the centre of the party’s agenda.
