Zohran Mamdani, the socialist mayoral candidate for New York City, is catching up to Andrew Cuomo in the polls for the Democratic primary. Mamdani, 33, is currently a New York assemblymember and has been running a grassroots campaign largely against former Governor Cuomo.

Cuomo is likely to get more first-choice votes than any other candidate.

Mr. Mamdani has been attacked by both Zionists and supporters of Palestinians, by rival mayoral candidates and by super PACs ready to spend millions of dollars on negative advertising in the last week...