Socialist Zohran Mamdani is surging and voters can rank five candidates in the crowded field. But will the anti-Cuomo candidates cooperate?

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.”

Andrew Cuomo faced a two-hour pile-on Wednesday as eight other Democrats vying for the party’s nomination for New York City mayor spent their first debate attempting to knock the former governor off his perch.