P resident Donald Trump warned Democratic mayoral primary winner and state Assemblyman Zohran Mamdani that if he becomes New York City mayor, he "better behave" or he will have "big problems," after Israeli Prime Minister Benjamin Netanyahu was asked if he's worried about Mamdani arresting him.

Mr. Mamdani’s victory upended city politics and reverberated nationally. He relied on a memorable message, charisma and a strong ground game.

On the campaign trail, Mamdani galvanized voters with his pitches on how to rein in the city’s sky-high cost of living, from fare-free buses to a rent freeze on rent-stabilized apartments.