Eric Adams says he wants to close Rikers. It may not be so simple.

As the Rikers Island jail complex descended into chaos this year, Eric Adams was clear: If elected, he would back Mayor Bill de Blasio’s watershed plan to close the notorious facility by 2027 and replace it with newer, smaller lockups across New York City.

But as Mr. Adams prepares to take office, his support for closing Rikers appears increasingly to be on a collision course with his promises to crack down on crime and accommodate local leaders’ opposition to the new jail sites.

It is unclear how, or if, the measure will survive the impact.

Where the current plan to replace the complex requires a sharp drop in the jail population, Mr. Adams has committed to policies that, in the near term, are likely to put more people behind bars. He has said he would restore a plainclothes police unit that was disbanded amid criticism of its aggressive tactics, and appoint tough-on-crime criminal court judges. He has urged state lawmakers to tighten bail laws that were recently loosened.

Mr. Adams has also expressed reservations about some of the sites selected for four new jails and has said he would show deference to two incoming City Council members who are furious about the prospect of jails opening in their districts.

And although the incoming mayor has not expressed it publicly, a person familiar with his thinking said that Mr. Adams was concerned that the $8 billion cost of the new jails could rise and said he would scrutinize the construction plans in light of a projected city budget crunch.

The conflicting messages combine to raise the possibility that a marquee criminal justice initiative of Mr. de Blasio’s tenure, which he pointed to regularly when questioned about poor conditions at the complex, could soon be materially rewritten or unravel entirely.

“There is a disconnect between thinking we can close Rikers and having policies that are invariably going to increase the population well beyond what we have now,” said Elizabeth Gaynes, who, as the chief executive of the Osborne Association, an organization that supports incarcerated people, has advised the city on its plan to close Rikers. “That’s just reality. It doesn’t compute.”

Hanging in the balance are the thousands of incarcerated people and jail officers at Rikers who are struggling through its worst crisis in years.

Although other jails in the United States have strained to operate during the coronavirus pandemic, New York City’s system stands apart for its high costs — more than $500,000 a year to house each detainee — and the broad outcry its conditions have prompted. Hundreds of officers have refused to show up for work. Delays in providing food, water and medical care for detainees have created what members of Congress have described as a humanitarian crisis.

Last week, Malcolm Boatwright, 28, became the 15th person to die this year after being held in the jail system. On Tuesday, William Brown, 55, became the 16th.

As the problems have intensified, Mr. de Blasio has doubled down on the plan to shutter the complex, saying it will remake the justice system in America’s largest city by de-emphasizing incarceration as a response to many crimes and replacing decrepit, dangerous conditions with more humane ones.

But in interviews, even some of Mr. de Blasio’s allies and former advisers have suggested that he has not always pushed the plan as aggressively as his rhetoric would suggest, leaving it vulnerable to setbacks.

After declining for years, the jail population has risen since summer 2020. Design and construction delays for the new jails have mounted, in part because of the pandemic, pushing the expected completion date from 2026 to 2027. A panel convened by the city to keep the plan on track has not met formally for more than a year.

Mr. Adams has not been afraid to buck his predecessor’s jail policies. In naming a new correction commissioner, Louis A. Molina, on Thursday, Mr. Adams took aim at Mr. de Blasio’s plan to eliminate solitary confinement at the jails, saying the punishment was necessary to rein in violence. The incoming mayor’s stance was cheered by the powerful union that represents correction officers, whose leaders Mr. Adams has courted.

The union’s leaders have fiercely opposed closing Rikers, but Mr. Adams has insisted that he is committed to doing so. “We are on track,” Mr. Adams said at the Thursday news conference. “I have stated that I believe we need to close Rikers Island. But while we are closing Rikers Island, you can’t have a facility where the gates and doors don’t work.”

Mr. Adams may also exercise short-term options that his predecessor has not. Gov. Kathy Hochul’s office has indicated privately to city officials that the state would be open to shifting control of two shuttered Manhattan prisons — one in Harlem; the other in Chelsea — to the city to ease problems at Rikers, according to three people familiar with the talks who were not authorized to discuss them publicly. The facilities would need considerable work to become operational.

Fully reversing the closure plan would prove difficult legally and politically, given the progress that Mr. de Blasio’s administration has made. The new borough-based jail sites have cleared the city’s byzantine land-use process, and the City Council has voted to prohibit people from being incarcerated at Rikers after 2027. But even minor tinkering by the new mayor could further mire the plan in delays.

In a statement, a spokesman for Mr. Adams said that the next mayor would have a “comprehensive plan” to address Rikers after he takes office and that Mr. Adams would take “a smarter approach to corrections policy that includes significant investment in mental health and substance abuse treatment as well as adequate capacity in the system to protect New Yorkers from dangerous individuals.”

The spokesman, Evan Thies, declined to make Mr. Adams available for an interview.

The plan to close Rikers

When Mr. de Blasio, a Democrat, announced in March 2017 that the city would close Rikers, he was under intense political pressure.

Federal prosecutors had investigated officers’ violence against young people incarcerated in the jails, and a federal monitor had been appointed to oversee efforts to improve conditions. Prominent leaders of the mayor’s own party, including the City Council speaker, had begun to demand its closure, urged on by formerly incarcerated people and their families.

An independent commission was days away from releasing a damning report recommending that Rikers, which has housed city jails since the 1930s, no longer be used for that purpose. The report detailed a lack of heating and air conditioning, crumbling walls, fixtures that could be fashioned into weapons and a persistent culture of violence.

Standing in the marble rotunda of City Hall, the mayor cast the decision as a turning point.

“This is a very serious, sober, forever decision,” Mr. de Blasio said then.

The plan, which the City Council passed in 2019, was never presented as an easy fix. It was predicated in part on the continuation of a marked drop in crime, and an attendant decrease in jail populations, and has been complicated by a rise in murders and shootings during the pandemic.

The plan also called for rethinking the use of bail and pretrial detention to shrink the jail population more than 70 percent so the system could fit into roughly 3,300 beds across four towers, one in each borough except Staten Island. (At present, there are about 5,400 people in New York City jails, most of them at Rikers.)

Only once those buildings had been approved and built could Rikers close in 2026.

“What people underestimate is how incredibly complicated this is,” said Elizabeth Glazer, the former leader of the mayor’s office of criminal justice. “It is one of the biggest infrastructure projects the city has ever seen.”

In a statement, a spokesman for Mr. de Blasio said the administration had moved “at record speeds” to put the new jail projects in motion and had not wavered from its 2017 commitments.

“The mayor made this plan a top priority, and committed $8 billion to completing the borough-based jail system, because he believes in his core that trading Rikers Island for smaller, safer jails is more than just good policy — it is a moral imperative,” the spokesman, Mitch Schwartz, said.

Mr. de Blasio’s support for closing the complex helped quiet some criticism as he sought re-election. In the years since, he has continued to promote the plan as his administration’s final word on the jail complex, including as it plunged into chaos this summer.

Touring the troubled facility in September — his first visit since 2017 — Mr. de Blasio declined to speak to incarcerated people who had been held in packed cells as the pandemic raged, or to correction officers who had worked double and triple shifts as hundreds of their colleagues did not come to work.

Afterward, he faced questions about what he planned to do with the jails. He repeatedly referred to his plan. “The real answer is to get off Rikers Island once and for all,” he said.

But the mayor’s critics and allies alike say he did not throw his full weight behind bringing about its closure or selling the plan.

“More could have been done under this administration to move the vision of closing Rikers forward and to realize it,” said Melissa Mark-Viverito, the former City Council speaker who was instrumental in prodding the mayor. “More should have been done.”

Ms. Glazer and others have questioned the city’s approach to accelerating the completion of the new jails by awarding contracts to a single company to design and build the four towers. The approach, they say, could backfire by limiting competition, lowering quality while increasing costs.

And advocates for detainees and correction officers say the mayor used the plan to dodge criticism rather than solve the underlying problems at the jail complex, which is slated to remain open at least another six years.

“It was always just a political maneuver for this mayor,” said Tina Luongo, the attorney in charge of the Legal Aid Society’s criminal defense practice.

Benny Boscio Jr., the president of the Correction Officers’ Benevolent Association, said that Mr. de Blasio had left Rikers “to rot” as a way of encouraging calls to close it.

“Broken cells, unsanitary conditions just so every time he is asked, the answer is we have to close it, we have to get off that island,” Mr. Boscio said, adding that Mr. Adams would usher in a “huge turnaround” in relations.

Dana Kaplan, one of Mr. de Blasio’s top advisers on the plan, rejected that criticism, saying that the administration had put in an “incredible amount of work” to solicit community input and keep up the Rikers facilities. But she acknowledged they had little say in what would come next.

The plan always delayed until after Mr. de Blasio was out of office some of the hardest political decisions — like finalizing designs for the new jails and determining how to gradually close the Rikers facilities — leaving it susceptible to reconsideration.

Mr. Adams has already raised concerns about building 20- and 30-story jails on two of the sites in question — in the South Bronx and in Manhattan’s Chinatown neighborhood — given residents’ fierce opposition. He has said he wants to accommodate new City Council members who represent Chinatown and the Queens site who campaigned against them this fall.

“I really want to have a conversation with those who are going to be my partners in the next four years,” he said Thursday. “But we are on the time track. We are going to adhere to that.”

Jonathan Lippman, the former chief judge of New York who led the independent commission that examined Rikers, said Mr. de Blasio should be lauded for setting the plan in motion.

“But no one should be taking credit for this horrible place there right now,” Mr. Lippman said. “Every single public official in this city and state should be saying, ‘Whatever we’ve done wasn’t enough, and we have to fix it now while we work toward a longer term solution.’”