Ruth Messinger, the trailblazing Jewish political leader who in 1997 became the first and only woman to win the Democratic nomination for New York City mayor, endorsed Zohran Mamdani on Monday. Her support came as the Democratic nominee launched his citywide “Five Boroughs Against Trump” tour in Manhattan, joined by Assemblyman Harvey Epstein and Rep. Jerry Nadler, co-chair of the Congressional Jewish Caucus, who had endorsed Mamdani after his primary victory.