The club, HK Dems, also gained the support of top Democrats from Manhattan’s West Side – elected officials who years ago would not have dared to oppose the once powerful Mr. McManus, 83.
The defeat — in an obscure race well down the ballot below the mayoral and City Council choices — marked an unceremonious end to a century of political dominance by the McManus club, the oldest Democratic club in the city and the last of the Tammany-era holdouts.
“They had the whole establishment against us, everybody,” said Mr. McManus, who helped nurture the political careers of many of the elected officials who opposed his club on Primary Day.
State Senator Brad Hoylman, a Democrat whose district includes Hell’s Kitchen, said Mr. McManus’ inability to get candidates elected in recent years weakened the club, as did its failure to keep up with a changing population that includes gay voters, younger voters and more professional constituents.
McManus was not the only longstanding political club to be defeated by an upstart formed in response to Mr. Trump’s election.
On the Lower East Side, two candidates from the newly formed Grand Street Democrats — Lee Berman and Caroline Laskow — capitalized on changing neighborhood demographics and grass-roots activism to beat incumbent candidates backed by the Harry S. Truman Democratic Club, the power base of former Assemblyman Sheldon Silver, who first took office in 1976 and held his seat until his conviction on federal corruption charges in 2015.
Like the Hell’s Kitchen club, the Grand Street club candidates criticized their entrenched opponents as being part of insular and outdated political machines.
In Hell’s Kitchen, the HK Dems club was founded several months ago by Marti Gould Cummings, a professional drag queen who, seething after Mr. Trump’s election, heeded a suggestion to create a political club.
“I said, ‘I don’t know what that is, but I’m going to start one,’” Mr. Cummings recalled.
He and other members harnessed a wide base of support for their candidates — Marisa Redanty,…