A Democratic Socialist state assemblyman, Zohran Mamdani, is closing the gap in the New York City Democratic mayoral primary race with less than four weeks until Election Day.

A new Emerson College poll finds Mr. Mamdani coming within nine points of Governor Cuomo in the final round of ranked choice voting, with the former governor winning in the 10th round with 54.4 percent of the vote.

Mr. Cuomo is still the clear frontrunner, but this latest poll shows his lead is slipping. Mr. Cuomo earns 35 percent of the vote in the first round to Mr. Mamdani’s 23 percent, according to the poll. The city comptroller, Brad Lander, earns 10.5 percent of the vote, with the rest of the candidates in the single digits. In subsequent rounds of voting, as other progressive candidates are eliminated, Mr. Mamdani wins second-choice votes against Mr. Cuomo at a margin of two-to-one.

“Cuomo has led in the polls since early 2025, but Mamdani has surged,” the executive director of Emerson College Polling, Spencer Kimball, said. “With four weeks to go, the question in whether Cuomo can run out the clock, or if he needs to win over second-choice voters to hold off Mamdani’s momentum.”

The Emerson poll is the first to show it taking Mr. Cuomo 10 rounds to break 50 percent, the requirement to win. Mr. Cuomo’s negatives also remain high, with 47 percent of Democratic voters viewing him unfavorably.

A Marist poll earlier this month found Mr. Cuomo winning in the sixth round of voting with 60 percent to Mr. Mamdani’s 40 percent. A Siena College poll in April showed Mr. Cuomo winning in the ninth round of voting with 64 percent to Mr. Mamdani’s 36 percent.

Mr. Mamdani is celebrating his showing in the Emerson poll. “We’re now 8 points away from sending Andrew Cuomo back to the suburbs,” he posted to X.

The Cuomo campaign is downplaying the poll. “This poll of registered voters appears to be an outlier, but the facts across the board remain the same — Andrew Cuomo is the consistent and overwhelming frontrunner in this race. That’s because New Yorkers know he is the only candidate in this race with the executive experience and the proven record of results to fix what’s broken and put this city back on the right track after 12 years of failed leadership,” a Cuomo spokesperson, Rich Azzopardi, tells the Sun by email.

“He’s running a better campaign,” the president of Sheinkopf Communications, Hank Sheinkopf, tells the Sun of Mr. Mamdani. “He’s effectively iced out Lander and Stringer, so he’s in a very good position. He could win this.”

Mr. Sheinkopf says this election will come down to turnout. Mr. Mamdani has mobilized the Democratic Socialists of America and young, white, college-educated New Yorkers. Mr. Cuomo, by contrast, is attracting older, working class, and minority voters. While Mr. Mamdani spouts about racial justice, his overwhelmingly white and privileged progressive base should come as no surprise.

Mr. Mamdani is also promising a rent freeze on all rent-regulated apartments in the city — a promise that other progressive candidates are also now making and that could help Mr. Mamdani boost turnout. There are nearly a million rent-regulated apartments in the city. Turnout in the last Democratic mayoral primary was also around a million. If he can get a large fraction of these tenants to vote in June, he could win.

This recent surge for Mr. Mamdani comes as he faces hot water for his membership in and endorsement from the Democratic Socialists of America. A faction of the DSA posted to X on Tuesday a statement that it is “justified to fight, by any means necessary” for the “Palestinian struggle.” On top of the statement, the DSA Liberation caucus wrote, “Free Elias Rodriguez and all political prisoners,” referring to the man who allegedly murdered two Israeli Embassy employees outside the Capital Jewish Museum in Washington, D.C., last week.

For a man who posts prolifically to social media, Mr. Mamdani has been uncharacteristically silent in condemning the DSA. The Mamdani campaign did not return the Sun’s request for comment.