Governor Cuomo, as New York Democrats call for Mayor Adams to resign or for Governor Hochul to remove him from office, is setting the stage for his own mayoral challenge by trying to peel away support for Mr. Adams in the black community.

Mr. Cuomo secured on Saturday his first major endorsement — from an elder statesman of the Black community, Carl McCall, who is a former New York Comptroller. In an open letter, Mr. McCall said that he has “never publicly urged a candidate to run for office,” but that “the dramatic decline in our quality of life” forced him to take action.

“The leadership of New York City has rarely, if ever, been as vital as it is today,” Mr. McCall said in an email. “The Mayor of New York must not only have the competence and capacity to manage the City’s real challenges, but the mayor must have the ability to defend our city and demonstrate a powerful counterbalance to President Trump.”

“For these reasons, I urge Governor Andrew Cuomo to run for Mayor of the City of New York and I offer my full support,” he emailed.

Mr. McCall echoed calls from other city Democrats that Mr. Adams is compromised and entered into an alleged quid pro quo with the Trump administration in exchange for them dropping the bribery, campaign finance, and corruption charges against him “without prejudice,” meaning they can be brought back at any time.

On Saturday, the State Senate Majority leader, Andrea Stewart-Cousins, called on Mr. Adams to resign. “It’s probably time that he move aside,” she told the New York Post.  

“We all know Donald Trump doesn’t do something for no reason at all. This case is not dismissed. It’s ‘without prejudice,’ which means they can keep hanging over the City of New York’s head,” a Black New York Congressman, Gregory Meeks, who is chairman of the Queens Democratic Party told The New York Sun.

The Democratic House minority leader, Hakeem Jeffries, said Thursday that, “It is the intention of the Trump administration to keep the current mayor on a short leash.” Black Democratic mayoral candidate Michael Blake called Mr. Adams a “puppet of Donald Trump” at a press conference on Thursday and urged Ms. Hochul to remove him from office.

Mr. Adams, appearing on  “Fox and Friends” Friday morning with Mr. Trump’s border czar Tom Homan, failed to dispel the talk of a quid pro quo in his dealings with the Trump administration and may have worsened his situation. “If he doesn’t come through I’ll be back in New York City. And we won’t be sitting on the couch, I’ll be in his office, up his butt, saying where the hell is the agreement we came to,” Mr. Homan said.

“I want to be crystal clear with New Yorkers: I never offered — nor did anyone offer on my behalf — any trade of my authority as your mayor for an end to my case. Never,” Mr. Adams posted to X later on Friday.

Ms. Hochul, for her part, has not closed the door on forcing Mr. Adams’ removal, though she seems unlikely to do so. “The allegations are extremely concerning and serious. But I cannot as the governor of this state have a knee jerk, politically motivated reaction like a lot of other people are saying right now,” Ms. Hochul told MSNBC’s Rachel Maddow. “This just happened. I need some time to process this and figure out the right approach.”

A Democratic strategist, Hank Sheinkopf, tells The New York Sun Ms. Hochul is unlikely to remove the mayor. “If she removes him, what happens to her?” he says. “She can’t take the risk of losing New York City votes because her polling numbers are atrocious today.”

Mr. Cuomo has not officially entered the mayor’s race, and his spokesman, Rich Azzopardi, consistently says it’s “premature” to set a timeline on when he will make that announcement. He has until April 3 to collect the necessary signatures to be on the primary ballot.

Mr. Sheinkopf says there’s no reason for Mr. Cuomo to rush. Mr. Cuomo has nearly $8 million in a state campaign account, much of which is not transferrable to a city campaign, and he has more leeway to spend it before he declares. Mr. Cuomo can also stay behind the scenes as progressive mayoral candidates battle it out and issue statements on Mr. Adams.

“If I’m him, I don’t announce before the petitions go out. Why would I put myself at risk?” Mr. Sheinkopf says.

Mr. Cuomo has been courting the Black vote since last year, attending regular Sunday services at Black churches. On Valentine’s Day, he released a campaign-style video at an event for seniors at the Johnson Houses Community Center in East Harlem. Most of the audience is Black.

“I missed you,” Mr. Cuomo says into a microphone. “No, we missed you,” a woman yells back. The video is intercut with black and Latino women hugging him.

Every recent poll shows Mr. Cuomo with a substantial lead in the Democratic mayoral primary. The other candidates in the race are running to Mr. Adams’ left. Voters’ top concerns are crime and public safety.

In the video, Mr. Cuomo addresses crime. “It’s frightening out there on those streets today,” he says. “But we know how to make this city work, and make this state safe for everyone, and that’s exactly what we’re going to do.”

New York’s first Black governor, David Paterson, told the Sun earlier that Mr. Cuomo needs to be careful not to be seen as trying to oust a black mayor. “Governor Cuomo spent most of the time that I was governor organizing to try to get me to leave, and I don’t know if a second time around that would be appreciated,” Governor Paterson said. “There could be a real backlash.”

Mr. McCall’s endorsement, which starts with a quote from Martin Luther King Jr., may come as a surprise to some. Messrs. McCall and Cuomo were fierce political opponents in the 2002 New York governor’s race, before Mr. Cuomo pulled out just before the primary. Mr. McCall secured the Democratic nomination but lost the election.

“Some might be surprised that I am supporting Andrew so strongly and so early,” Mr. McCall said in his letter. “But despite how it was framed in the press, we were never political adversaries.”

Mr. Cuomo issued a press statement on the McCall endorsement just minutes after its release. “Carl McCall is a legendary public servant who broke barriers and served as a role model for a generation of democratic elected officials,” Mr. Cuomo said. “I thank him for his faith in me and for his advice, trust, and confidence.”