Zohran Mamdani has buzz and some momentum in New York City’s mayoral race. But can a 33-year-old democratic socialist — or anyone else — beat former Gov. Andrew Cuomo in the Democratic primary? Mamdani picked up a key endorsement Thursday from U.

The progressive congresswoman is supporting the young Queens assemblyman’s upstart campaign in a crowded Democratic primary field.

The decision by Ms. Ramos, a state senator from Queens, is at odds with her frequent criticism of Andrew M. Cuomo, including comments questioning his “mental acuity.”