Everybody is talking about Zohran Mamdani, the state legislator and New York City Democratic mayoral nominee who has become a national news story. But not everyone understands why Mamdani has captured so much attention.

Fresh off losing New York’s Democratic primary for mayor to Zohran Mamdani, former Gov. Andrew Cuomo on Monday ramped up his efforts to push the incumbent mayor, Eric Adams, out of the race.

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