Mayor Eric Adams and his outsider pick for NYPD commissioner will have to walk a “fine line” as they try to address the unresolved issues of the outgoing administration, police experts tell The Post.

Adams and new top cop Keechant Sewell have inherited a city wracked by surging gun violence and an annual murder rate frighteningly close to 500 for the first time in a decade.

Adams — the self-proclaimed “face of the Democratic Party” and a former NYPD captain who secured his mayoral win as a law-and-order leader — has made it clear he wants the Big Apple to serve as a blueprint for crime-fighting for other major cities.

Much of that challenge will fall on Sewell — who has said she plans to hit the ground running with a “laser focus” on cracking down on gun crime.

But lowering the city’s crime rate will take time, experts say.

“The biggest challenge is early expectations that are unrealistic,” said Maria Haberfeld, a police science professor at John Jay College of Criminal Justice in Manhattan. “It will take a host of variables to deal effectively with what was created by Mayor Bill de Blasio.

“There will be a lot of pressure for this to disappear as quickly as possible,” Haberfeld said of the city’s recent violent surge.

“[And] when there’s a lot of pressure for change, mistakes are made,” she warned.

Here is a deeper dive into the challenges the Adams administration will face:

Slowing the surge of gun violence and slayings

In the Big Apple, shootings have soared since the early weeks of the COVID-19 pandemic, doubling the totals of 2019 each year. That uptick has also led to a rate of homicides not seen in a decade.

As of Sunday, there were 479 murders and 1,546 shootings, compared to 319 and 777, respectively, for the full year in 2019. The last time the NYPD recorded more than 500 homicides in a year was in 2011.

The disturbing trend is not unique to New York City, noted Thomas Abt, a senior fellow at the independent think tank Council on Criminal Justice and current chair of the organization’s Violent Crime Working Group.

“I think Adams is going to face a similar challenge that most mayors are facing right now, which is high levels of gun violence during a time when resources are stretched thin by the pandemic and people are more polarized than ever,” Abt said. “New York is struggling with those issues, just like other cities in the country.”

Adams and Sewell have promised to crack down on gun violence by bringing back the NYPD’s controversial anti-crime unit, but Abt warned that the new administration will have to “walk a fine line” amid inevitable criticism.

“Tough-on-crime people say we should make more arrests,” he said. “Soft-on-crime people say we should make fewer arrests.”

That delicate balance also applies to employing aggressive policing tactics such as stop and frisk, which Abt suggested being used “as necessary, and no more.”

He said the department needs to focus on the quality of arrests.

“If violence is a cancer, then aggressive policing is chemotherapy,” Abt said. “Chemotherapy is an important tool in fighting cancer, but it’s also harmful to the patient. And so what we do is use chemotherapy, but use it as little as possible. Use it as a last resort.”

Richard Aborn, president of the Citizens Crime Commission of New York City, said the recent record number of gun arrests by other undercover units is proof that similar patrols can be out on the streets without causing the controversy the anti-crime unit caused.

“We need to learn the lessons of what went wrong, which is a lot around supervision, and make sure that doesn’t happen again,” he said.

Still, Haberfeld said that bringing back the anti-crime unit will be a challenge “because it was portrayed as the epitome of police misconduct.”

Community engagement

No matter how sparingly aggressive tactics are used, experts say there still needs to be community buy-in on how the NYPD operates in neighborhoods.

And that buy-in comes from working with residents and connecting with them, according to experts.

“I think building community ties is absolutely essential for everything involved in public safety, not just homicide clearance rates,” Abt said.

Aborn said the new administration can help by fostering “constant, open communication with those communities where the most policing is taking place so that residents understand why the NYPD is doing whatever it’s doing.”

“That sort of transparency, that sort of line of communication, will help ease tensions in and of itself,” he said.

Both Aborn and Abt said they believe Adams and Sewell have the potential to easily open that line of dialogue with communities.

The commissioner needs to “communicate with those communities where there’s a lot of policing taking place and can explain why,” Aborn said. “She seems really quite skilled at that. And clearly, Adams is, too.”

Abt agreed, saying “Adams and Sewell are well-positioned to do this.

“The fact that they’re both African-American members of law enforcement or in Adams’ case, a former member, means that they can speak to multiple communities with moral authority,” Abt said.

“They know what it’s like to be profiled, and they know what it’s like to go to a crime scene and have to comfort victims and search for perpetrators, and I think that means they may be able to find some kind of middle ground.”

An outsider pick to run the department

Sewell, Nassau County’s former chief of detectives, is the first woman to ever run the NYPD — and also the first leader with no ties to the force since Bill Bratton’s first tenure in the mid-1990s.

Haberfeld said that to have a leader who isn’t “tainted by departmental culture and politics” could be good for the NYPD.

“The [outsider] has a maybe more objective view and look at things,” she said.

But it could also go the other way, Haberfeld said.

“The negative, of course, is that because it’s an outsider, no doubt [there is] already a resentment built in from the troops because people want to believe that … ‘One day, I can become a commissioner’ and anything is possible [in the department],” he said.

“Suddenly, they think that now it’s not possible because they bring in an outsider, so it has a negative impact on overall morale.”

Haberfeld noted the Sewell’s selection could make other women in the department “proud and hopeful” to see “somebody who epitomizes success” in the male-dominated policing profession.

“But at the same time, again, if we’re looking at high-ranking female police officers within the NYPD, they might be resentful,” he said of the other women cops. “People think, you know, 20 years to this department and now being passed over for an outsider.

“So, it’s really a very challenging and mixed bag for her in terms of potential success.”

Police morale

Experts say morale is already a “big problem” on the force after eight years with the de Blasio administration, which was at constant odds with the rank-and-file since the start.

“She’s going to have to adjust that quickly,” Aborn said of Sewell.

“As much as we talk about the external legitimacy of the NYPD, I think we also have to address internal legitimacy,” Aborn said. “How do the men and women of the department view the leadership? Do they see them as open honest, transparent, forthcoming? Do they see them as backing them up?

“That’s not a minor challenge, it’s a very dispirited department,” he said.

Both Haberfeld and Aborn said morale has led to a drain of experienced cops from the NYPD.

“You have to keep recruiting, but those recruits still won’t become senior talent for 20 years,” Aborn said. “Not all, but a lot, of your senior talent is going out the door. They retired. They voted with their feet.

“She’s gonna have to contend with that.”

Sewell, though — despite all the challenges facing the NYPD and only having under two years managing a few hundred detectives in Nassau County — has been steadfast in her ability to overcome the problems, telling The Post she is “here to meet the moment.”

“Come and talk to me in a year,” the top cop said in her first media appearance when asked about criticism that she wasn’t experienced enough to lead the nation’s largest police force.

Police experts say all these issues wouldn’t disappear overnight — and that the crime rate could take years to return to pre-pandemic levels.

But any change in the trends would be a success for Adams and his surprise pick for police commissioner, the experts believe.

“I think that ultimately what matters is trends,” Abt said.

“If murders and violent crime are trending down, they’ll be able to make their case,” he said of Adams and Sewell. “If it’s trending up, they won’t.”