While New York State Assemblyman Zohran Mamdani won New York City’s Democratic mayoral primary by a sizable margin, pollster Nate Silver argued on Tuesday that “in theory,” the socialist front-runner “could be vulnerable” in the November general election.

Silver discussed his thoughts on Mamdani’s primary win in his Substack newsletter, saying his victory margin against former Gov. Andrew Cuomo and other candidates may not be good enough to overcome other factors.