'Staggering': Ex-NYC mayor stunned watching 'amazing upset'
Assemblyman Zohran Mamdani speaks during the New York City Democratic Mayoral Primary Debate at the John Jay College of Criminal Justice in the Gerald W. Lynch Theater in New York City., U.S., June 12, 2025. Vincent Alban/Pool via REUTERS

Former New York City Mayor Bill de Blasio called Zoran Mamdani’s commanding lead in the Democratic mayoral primary a “staggering” development Tuesday night, and added that the Democratic socialist’s strong performance marked “an amazing upset” in the nation’s largest city.

Reacting on CNN as the network projected the closely watched race would head to ranked-choice tabulations with Mamdani falling short of the 50% threshold, de Blasio said he was surprised to see former Gov. Andrew Cuomo – widely seen as the frontrunner heading into election night – in second place.

“It's an amazing upset,” de Blasio told CNN’s Kaitlan Collins. “When you look at this number right now, this lead that Zohran Mamdani has right now with the early vote numbers – which were staggering – 25% of all early votes were people who had never voted in a New York City election. And we know a lot of that was younger voters coming out for him."

He added: “This looks like he's in a very strong position to be declared the winner when the full count is done on July 1.”

De Blasio, who Collins noted had previously urged voters not to rank Cuomo, credited Mamdani’s “positive campaign,” he said was centered on affordability and housing, while he slammed Cuomo for what he called “a very negative, fear-based campaign.”

“This has made a huge difference,” the ex-New York City mayor said Tuesday on CNN as votes continued to be counted. “People at this point in New York City, they are hurting for sure, but they didn't just want to hear how bad everything was.”

He said New Yorkers instead “wanted to have some sense of hope, some sense of solution and vision.”

Cuomo late Tuesday conceded the race and congratulated Mamdani, the New York Times reported.

“Tonight was not our night,” Cuomo told supporters. “Tonight is his night. He deserved it. He won,” the former governor added of Mamdani.

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