Abetting two recently established PACs spending millions to defeat two of New York City Mayor Zohran Mamdani’s candidates for Congress is a veteran politician who sought Gracie Mansion last year — former City Comptroller Scott Stringer, according to multiple sources with knowledge of the committees and their activities.

Stringer declined to comment on the record for this story. But Jewish Insider first reported in March that the Upper West Side Democrat was a key force behind a political committee, Next NYC PAC, committed to defeating the Democratic Socialists of America’s candidates for Assembly and state Senate.

According to several individuals who spoke on the condition of anonymity to protect their relationships, the team behind the Progressive Unity Fund and Real Fight NYC PACs — which have released a wave of ads attacking activist Darializa Avila Chevalier and Assemblymember Claire Valdez, Mamdani’s candidates to defeat Rep. Adriano Espaillat (D-NY) and replace retiring Rep. Nydia Velazquez (D-NY), respectively — overlaps considerably with the personnel behind Next NYC PAC. This includes consultant David Keith, as well as the firm of longtime Rahm Emanuel operative Greg Goldner, who ran former New York Gov. Andrew Cuomo’s campaign for mayor in the last weeks of the 2025 race.

However, sources said Goldner was not personally involved in either PAC, which have each made only a few minimal disclosures to date, although an employee of his Next Public Affairs appears in the source code of Progressive Unity Fund’s webpage. Goldner and Next Public Affairs did not respond to a request for comment from JI.

Stringer has no formal position or title with either group, sources said, but has been deeply involved in their organization and operations. His former comptroller campaign and inaugural committee treasurer, Peter Frank, holds the same role with Progressive Unity Fund. Frank told JI he had “nothing to offer” for this story.

Stringer recently shared an ad from Progressive Unity Fund attacking Avila Chevalier on his X account.

Stringer also provides a key link to the primary funder of both PACs, the American Federation of Teachers. AFT President Randi Weingarten — who formerly led the New York City’s United Federation of Teachers, which has deep ties to Stringer and the Upper West Side Democratic establishment — confirmed to City & State on Tuesday that her union was underwriting the ads attacking Valdez and Avila Chevalier.

In the interview, Weingarten rejected baseless suggestions from Valdez that AIPAC had a role in Real Fight NYC. The AFT did not respond to repeated requests for comment for this article.

According to the latest FEC filings, Progressive Unity Fund and Next NYC PAC together have spent more than $2.1 million to date.

Jennifer Bayer-Michaels, a longtime Cuomo fundraiser and prominent pro-Israel Democrat, as well as a key figure in Next NYC PAC, is not involved in these two federal committees, she and several other sources attested. She is, however, working with an unrelated pro-Espaillat committee.

For most of his political career — which included stints in the state Legislature and the Manhattan borough presidency — Stringer counted among the city’s most liberal political figures, reflecting the deep-blue proclivities of his Manhattan voter base. But by the time he made his second bid for mayor in 2025, he cut a lonely figure on the debate stage by declaring himself a Zionist. He ultimately placed fifth in the competition.