President Trump is ramping up his attacks on one of the GOP's newest targets, New York City's progressive mayoral candidate Zohran Mamdani.

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

The president, who has a history of spewing sometimes vile insults at rivals, has in recent days escalated his attacks against the 33-year-old self-described democratic socialist. Trump has threatened to arrest Mamdani, to deport him and even to take over the country’s largest city if he wins the general election in November.