Of broken-windows policing, Bratton said, “I rely on what my eyes show me.” Photograph by Pari Dukovic for The New Yorker

On a bitterly cold night in February, William Bratton, New York City’s police commissioner, joined several hundred uniformed officers for an informal memorial service at the corner of 107th Avenue and Inwood Street, in Jamaica, Queens. It was past midnight, and everyone was waiting for Mayor Bill de Blasio, who was due to speak. Twenty-seven years earlier, on February 26, 1988, a twenty-two-year-old officer named Edward Byrne was shot and killed on that corner, on orders from a drug dealer, as he sat in his patrol car guarding the home of a witness. The memorial is an annual rite for many city cops, and is a reminder of how much tougher New York’s streets were at the time of the murder. That year, there were eighteen hundred and ninety-six homicides in the city, many of them drug-related. In 2014, there were three hundred and twenty-eight, a record low. Byrne’s death drew national headlines, and President Reagan phoned the Byrne family to offer his condolences.

Before the service, the Mayor’s staff worried privately about how the officers would greet him. Under Mayor Michael Bloomberg and Police Commissioner Raymond Kelly, the use of stop-and-frisk—in which officers stop, question, and pat down someone if there is a “reasonable suspicion” that a crime has occurred or might occur—became more frequent, and minority leaders were speaking out against the aggressive tactics of the N.Y.P.D. De Blasio, while campaigning for mayor, had called for more civilian oversight of the police, and vowed to crack down on “discriminatory” police practices. The comment did not sit well with many cops. “He ran an anti-police campaign,” Kelly told me recently. “He parsed the electorate. He did it very skillfully. He aimed at the fringes.”

In appointing Bratton, de Blasio hoped to reassure both the public and the police. Bratton, who is sixty-seven, served as New York’s police commissioner from 1994 to 1996, under Mayor Rudolph Giuliani, and oversaw a sharp reduction in crime. From 2002 to 2009, when he was the chief of police in Los Angeles, violent crime there fell by fifty-four per cent. Bratton embraced both stop-and-frisk and broken-windows policing, the latter a strategy based on the idea, proposed in 1982 by the sociologists James Q. Wilson and George L. Kelling, that cracking down on “quality of life” crimes and disorderly behavior—turnstile-jumping, squeegee men, public intoxication, aggressive panhandling—makes citizens feel safer and discourages more serious crime. In 2009, a Los Angeles Times poll showed that eight of ten voters, including seventy-six per cent of Latinos and sixty-eight per cent of blacks, approved of the L.A.P.D.’s performance.

Upon returning to New York, Bratton confronted a police force that had serious issues. A survey of seventeen thousand city residents, ordered by Bratton and conducted in May and June of 2014, found that forty-one per cent of blacks and thirty-one per cent of Hispanics held a somewhat negative or very negative view of the police, compared with just seventeen per cent of whites. A second survey, involving a third of the city’s force of thirty-five thousand officers, revealed that seventy per cent of them lacked confidence that their decisions “would be backed by the department.” Three-quarters of white cops said that they expected fair treatment from their supervisors, but only a third of black officers and half of Latino officers felt that way. Before hiring Bratton, de Blasio called the two former mayors of Los Angeles whom Bratton had worked for, and both assured him that Bratton believed that communities and the police must work together to combat crime. Bratton “understood that policing had to be community-focussed and constitutional,” the former Los Angeles mayor Antonio Villaraigosa told me. Bratton helped convince de Blasio that broken-windows policing was effective, but he also agreed that the N.Y.P.D.’s use of stop-and-frisk was excessive.

Then, in July of 2014, came the death of Eric Garner, a forty-three-year-old black man arrested on Staten Island for illegally selling loose cigarettes—a classic broken-windows offense. According to the medical examiner, Garner died after being put in a choke hold by police, who were trying to restrain him, but no officer was indicted; a federal investigation is still under way. (On July 13th, the city agreed to pay the Garner family $5.9 million to settle a wrongful-death lawsuit.) The following month, in Ferguson, Missouri, Michael Brown, an unarmed eighteen-year-old black man, was shot and killed after an encounter with a white officer. That officer, too, was not indicted by a grand jury, and protests erupted in New York and other cities. In a press conference, de Blasio, who has a biracial son, admitted that he and his wife have “had to literally train” him in “how to take special care in any encounter he has with the police officers who are there to protect him.” Patrick Lynch, the president of the Patrolmen’s Benevolent Association, complained to the press that de Blasio had thrown cops “under the bus.” Then, in December, a mentally ill man shot and killed two officers as they sat in their patrol car in Brooklyn, after which he killed himself. Lynch declared that de Blasio had “blood on the hands,” and, when the Mayor met with grieving family members, a wall of police officers turned their backs on him.

Recently, Bratton defended de Blasio’s remarks about his son: “Every black I’ve ever dealt with tells me that they tell their kids the same thing. Don’t you as a white parent tell your kids certain things when they’re going out driving?” He added, “Not being black, how do we put ourselves into his shoes?”

At the memorial service in Queens, de Blasio, who is six feet five, towered over Bratton, who is five-ten. He wore a blue police windbreaker with the word “Mayor” emblazoned in yellow across the back. With his hands clasped in front, he followed and seemed to defer to Bratton, who introduced him to members of the Byrne family. Patrick Lynch was there but did not offer to shake hands, and de Blasio avoided eye contact. Bratton addressed the crowd, saying of Byrne, “His life, his sacrifice, began a change in this city.” He talked about the unity of the N.Y.P.D. “family,” a word that was mentioned several times that night. The Mayor then spoke, and concluded, tepidly, “Tonight, it’s so important just to remember a good young man, a good young man who represented all that we aspire to be.” Afterward, a senior police official whispered to me, “He’s passionate about pre-K. I guess he’s not passionate about cops.”

Not long ago, I joined Bratton in his black S.U.V., as he was being driven to a farewell reception for the retiring commander of Brooklyn South, at the Sixty-seventh Precinct, in East Flatbush. He told me that the winter and early spring had been “the most trying period of time for me in my whole career. If you look at the turbulence, not only in the city but the country, you had attacks on the police, you had anti-police momentum being generated by Washington and Eric Holder”—the Attorney General, who in March declared that the people of Ferguson feel “under siege” from the police. “And, at the same time, police were saying, ‘This is crazy. We are saving America.’ ”