Beyond his social media talent and approaches on affordability and Israel, Democratic voters have been inching to the left for years.

NEW YORK — Vermont Senator Bernie Sanders is urging Democratic Party leaders to rally behind Zohran Mamdani, whose surprise victory in the New York City Democratic mayoral primary has made him a target of intensifying anti-Muslim hate online.

Zohran Mamdani, a 33-year-old democratic socialist, has clinched the Democratic nomination for mayor of New York City, besting a crowded field that included former governor Andrew M. Cuomo.