The video initially looks like a standard campaign spot: Zohran Mamdani and Kathy Hochul introduce themselves as they walk through a sunlit park. As the 43-second clip unfolds, however, the staged conversation takes a decidedly darker turn. Mamdani, New York City’s mayor, and Hochul, the state’s governor, are presented in an unflattering way. A narrator even calls Hochul “the political...