Mamdani had faced down a robust funding campaign by the nation’s ultra-rich in favor of his opponent, Andrew Cuomo, the disgraced former New York governor who ran as an independent in the mayoral race after Mamdani defeated him in a landslide upset victory this past summer. (The Republican ballot line featured Curtis Sliwa, a perennial mayoral candidate and New York City eccentric who was not a real contender in the race.) Billionaires, perturbed by Mamdani’s avowed socialist politics, his proposals for expanded social services like universal childcare, and his declarations that billionaires should not exist, had backed Cuomo with a fervor that at times bordered on mania.