New York City Comptroller Brad Lander has announced his campaign for the city's 10th Congressional District, entering the race with the endorsement of Mayor-elect Zohran Mamdani. Lander's bid comes after Representative Dan Goldman declined to support Mamdani's mayoral run, a move that has now led Mamdani to back Lander against Goldman. The contest highlights deepening divisions within the Democratic Party, as Lander positions himself as a progressive challenger, focusing on issues like the war in Gaza and immigration, while Goldman emphasizes his moderate record and opposition to the Trump administration.

Lander's campaign launch featured criticism of Goldman's ties to major donors and his status as an heir to a prominent fortune, framing the race as a battle against entrenched interests. Meanwhile, Mamdani's endorsement signals a shift in alliances following his own upset victory in the mayoral primary, with progressive candidates gaining momentum in key races. The Democratic Party continues to grapple with internal disagreements and the challenge of presenting a unified front ahead of the upcoming midterm elections.

Other progressive figures, such as City Councilmember Chi Ossé, have withdrawn from congressional challenges due to lack of support from key groups, underscoring the importance of endorsements in shaping the field. As the campaign unfolds, Lander aims to capitalize on Mamdani's success and the growing influence of progressive politics in New York City.