The two Newark cops, Big Cat and Gesuelli, pulled up in their battered sedan and went to do some frisking in the courtyard of the old-age home. They stepped fast across the dark, almost empty quad, Big Cat in his black sweatshirt and Gesuelli in his gray one, toward a group in wheelchairs, two men and a woman. They looked to be in their 20s or 30s. Disabled people were housed in the city-run complex along with seniors. “You don’t mind if I pat you down,” Big Cat said to one of the guys—thighs visibly wasted beneath blue jeans, cap visor stylishly sideways.

There had been reports of drug dealing in the courtyard. Gesuelli scanned the pavement and a shrub bed with his flashlight, checking for anything that might have been tossed as the officers approached. “You can pat me down,” the guy in the cap answered, though Big Cat wasn’t exactly giving him a choice. “I’m good.” His white T-shirt glowed a little in the night. Big Cat moved his hands slowly down the atrophied legs.

“It’s not racially driven profiling,” Newark’s police director told me about the stops carried out by his officers. “It’s crime-driven profiling.”

“Let me ask you,” the woman put in, her half-laced high-tops on the footrests of her wheelchair, “is it a certain time we can come outside and enjoy some fresh air? Because it’s embarrassing to get harassed by the police.”

Big Cat—Officer Anthony Maldonado—and his partner, Bernard Gesuelli Jr., are in Newark’s Crime Suppression Unit. They do a lot of stopping and frisking. Or, as the Newark Police Department prefers to phrase it, “field inquiries.” “We don’t use stop-and-frisk,” the city’s police director, Samuel DeMaio, had explained to me before I began spending shifts with Big Cat and Gesuelli. “It sounds too invasive.”

This was last fall. Across the water, in Manhattan, a federal judge had just ruled against the New York Police Department’s stop-and-frisk program, condemning it as rife with unreasonable stops and searches and riddled with “indirect racial profiling.” Of those waylaid in New York between 2004 and June 2012, 83 percent were black or Hispanic. Newark’s current percentage is slightly lower.

The three people in wheelchairs were all black; so was another man who sat with them, wearing a tank top that displayed his muscles, and a do-rag with a long train down his back. “When was the last time you got arrested?,” Big Cat asked him, fingering the outside of his pockets, then around his knees, his ankles.

“Two, three years ago.”

The woman got no reply to her question.

In Newark’s Second Precinct, Detective Eugenio Gonzalez (left) and Officer Anthony "Big Cat" Maldonado (right) stop a car because its taillights are out, then question the driver. He receives two vehicle-related summonses.

Finished with the muscle-bound man, Big Cat glanced again at the one in the cap, then stared, recognizing his face, recalling that he’d allegedly played a part in a recent gang incident in the high-rise above us: someone had been shot in the head. “He’s a Crip,” the cop mumbled to me, sure he was dealing. “He’s slinging. He’s got a big knot”—a wad of cash in one of his front pockets. But the frisking and the flashlight turned up nothing criminal: no weapon, no contraband—two of a cop’s prime goals in any stop.

In cities across the country, stop-and-frisk strategies have gained great currency. They aim to get guns off the street, to glean information and solve crime sprees, and, perhaps above all, to act as a deterrent, by letting criminals and would-be lawbreakers know that they might find themselves getting a pat-down at any given moment. Arguably, the policies have succeeded, helping to cut crime dramatically from New York to Los Angeles. But they have also stirred the loudest and most painful present debate in American criminology: Are young men of color being unfairly—and unconstitutionally—singled out?

“I know you,” Big Cat said to the possible Crip, not unpleasantly. The two cops headed back to their car and drove on.

They’d started their shift an hour earlier, when the desk officer had buzzed them through a heavy door at the Second Precinct station house, a ramshackle castle of a building with a crenellated brick turret that looms over a desolate street corner in the North Ward. They’d walked past the department’s MOST WANTED poster: alleged murderers and men accused of carjacking or of shooting at an officer. All were men of color. They’d continued into a room of bulletin boards covered with mug shots of other wanted men, a panorama of nonwhite faces rendering a stark picture of who commits the vast majority of violent crime in Newark, as in many other American cities. Then they’d gone out in plainclothes to crisscross the ward, with its weary-looking wooden homes, its boarded-up buildings, its island of fancy houses, its weedy lots.

Big Cat, a 20-year veteran in the department, is light brown, Puerto Rican. He’s tall and bulky, but despite his size he has an aura of agility—hence the nickname. Gesuelli, nine years in, is white, Italian Irish, not so tall, soft around the middle. He grew up in the North Ward, on a block of modest homes that’s held its own amid Newark’s struggles. His father has a small wholesale-liquor establishment in the neighborhood. Big Cat spent his childhood across town; his parents make and clean molds for a tool-and-die company.

In 2011, the NYPD recorded 686,000 stops. Only about 12 percent ended in an arrest or a summons.

Early in their shift, they turned into a Dunkin’ Donuts drive-through, Gesuelli for a regular coffee and Big Cat for a latte. Leaving, they spotted three Hispanic men standing outside a fence bordering the parking lot. Did these three meet the Supreme Court’s guidelines for reasonable suspicion? Did they look, from a rational perspective, like they might be criminals? Did they fulfill the legal criteria for a stop?

Maybe not, but this didn’t necessarily matter to Big Cat and Gesuelli: two of the men were drinking what were surely beers in paper bags while on the street, and in the current era of what’s known as proactive policing, this minor offense frequently serves as a basis for a field inquiry. The guys stood around a car, one of them sucking on a lollipop. The cops approached and started asking questions. In the backseat, a little boy watched a video on a smartphone. A woman and an 8- or 10-year-old girl emerged from the Dunkin’ Donuts with a drink tray and a donut sack and walked over. “That’s my husband,” the woman said. “What’s going on?”

“Your husband will explain to you later.”

In level tones, the cops asked the men where they lived, where they worked. They collected IDs and used their phones to run warrant checks. (The officers weren’t looking for immigration problems—that’s not part of their mission.) This went on for 10 minutes, with the two kids in the car. “He’s missing teeth,” Big Cat said to me, nodding toward the skinny one with the lollipop. “Either he’s got a bad dental plan or he’s smoking crack.”

“We know you doing your job, making me safe,” one of the men offered—sincerely or snidely or in supplication, it was impossible to tell. The checks came back clean. Gesuelli wrote out summonses for public consumption, and the cops went on their way.

Pedestrians, including Tee Wilson (left), a local shop owner, gather on the street to watch as Newark police stop and frisk a group of men on the corner of Clinton Avenue and South 11th Street.

Had the men been white, would the patrolmen have been so eager to bother them about two open beers? They’d chosen not to do pat-downs, but with two white children present, would they have even prolonged the encounter with the questions and the warrant checks? I asked them about how race plays into field inquiries, into who gets stopped and what happens from there.

“The race card is burned out,” Gesuelli said.

“People need to get off it,” Big Cat added.

“It irks the shit out of me,” Gesuelli said. “Your skin color don’t mean nothing for me. If you’re looking like you’re up to a crime—”

“Some people out here are good, but …” Big Cat’s voice drifted off.

One of the reasons stop-and-frisk has stoked such outrage in the past few years, rousing civil-rights advocates from Philadelphia to San Francisco and all but deciding last November’s mayoral race in New York City, is the accusation that a great many blameless young students of color are being accosted and humiliated on a regular basis. Big Cat and Gesuelli’s next inquiry seemed to bear out the accusation.

On a seedy block, they heard a thunk, glanced over and saw two young black men, and guessed that one of them had noticed the cops and thrown a gun under a parked car. The officers jumped out. “Up against the car! Up against it!” Right away, it became clear that the men had gotten rid of nothing worse than a half-full can of beer, which lay beneath a bumper. “Spread ’em. Keep ’em out.” Obediently, the men lifted their arms and parted their legs. When the cops asked whether they worked, one of them—wearing a striped shirt on his narrow frame, sporting thin-soled slip-on sneakers, and looking more hipster than gangster—said softly that he was an assistant to a dental hygienist and was studying to be a nurse.

Maldonado uses his phone to confirm the identity of a subject.

Late last summer, after a nine-week civil trial, Judge Shira A. Scheindlin, of the U.S. District Court for the Southern District of New York, declared the NYPD’s stop-and-frisk policy unconstitutional. The ruling may help bring about the first profound national change in policing in at least 20 years.

Judge Scheindlin didn’t mince words. The policy, she pronounced, was discriminatory, and showed little regard for the requirement that stops be based on rational grounds. It had led repeatedly to violations of the Fourth and Fourteenth Amendments. Before, during, and after the trial, the NYPD argued that racial bias had nothing to do with its method, and that stop-and-frisk has been integral to the spectacular drop in crime—in murders and rapes, robberies and burglaries—that the city has seen in recent times.

To understand modern American thinking about the role of the police, it helps to focus on three documents. The first, a 350-page report titled “The Challenge of Crime in a Free Society,” was produced by a commission of legal luminaries appointed by Lyndon Johnson to address “the urgency of the Nation’s crime problem and the depth of ignorance about it.” Published in 1967, its rhetoric and recommendations reflect the ethos of its period. It is fundamentally optimistic, calling for the elimination of “social conditions closely associated with crime.” It highlights the need to strengthen families and improve schools, to end segregation in housing and education, to create programs for vocational training and opportunities for employment. Only after its insistence on grand social transformation does the report turn to policing. And it doesn’t much imagine that cops can play a major role in crime prevention. What they can do, it allows, is respond more swiftly after crimes have occurred, and thus bump up the odds of catching perpetrators. So it suggests that police departments add more call boxes.

“The race card is burned out,” Gesuelli said. “People need to get off it,” Big Cat added.

National crime rates jumped relentlessly in the 1960s and ’70s, and then again in the ’80s. This had the effect of confirming that cops couldn’t deter criminality, that they were merely a reactive force. And it hinted at something worse: that they might be downright helpless. As Great Society ideals faded, the main crime-control policy the nation could muster was to lock up more lawbreakers and keep them away for longer. More reactive criminology.

An article published in this magazine in 1982 titled “Broken Windows” helped spur a gradual reversal. This is the second document worth focusing on. Written by the social scientists James Q. Wilson and George L. Kelling, the article made the case for preventive policing. “Social psychologists and police officers tend to agree that if a window in a building is broken and is left unrepaired, all the rest of the windows will soon be broken,” Wilson and Kelling wrote, adding, “One unrepaired broken window is a signal that no one cares, and so breaking more windows costs nothing.” By imposing a bit of control in a neighborhood, they argued, by paying attention to minor crimes like panhandling and prostitution and by asserting authority over people who may not be criminals at all (“the ill-smelling drunk, the rowdy teenager”), police could strongly affect whether residents feel safe, and whether an area spirals downward or finds stability, remains abject or revives.

The article is widely credited with launching the modern era of proactive law enforcement. But the new emphasis on prevention that it encouraged led to the aggressive stop-and-frisk strategies that have provoked so much outcry. “Every time I read the ‘Broken Windows’ article, I get more upset,” says Udi Ofer, the executive director of the American Civil Liberties Union of New Jersey, who is considering a legal challenge to Newark’s stop-and-frisk program. (This would be in addition to the federal monitor reportedly soon to be assigned to Newark’s force by the U.S. Department of Justice, in response to a 2010 ACLU petition about a range of police abuses.) “Broken-windows policing,” he claims, gives cops far too much discretionary power in deciding what is suspect behavior, who might be up to no good, and what to do about it. “Under the rubric of broken windows,” he says, “comes racial profiling.”

As the cops stopped and frisked the assistant to the dental hygienist, Big Cat asked where he was going. A Chicken Shack, the guy said, to get something to eat. I leaned toward believing him about his job and about training to be a nurse. But his warrant check came back positive, so the cops took him to the station house in cuffs, where he confessed to having given his brother’s name the first time he was asked. A second check brought up even more warrants. An officer searched him thoroughly outside the cells. When his shirt came off, it became pretty clear that he was a gang member. He was covered in telltale tattoos: an arrangement of big stars on his arm, and Newark’s area code more than once on his upper body.

Detective Eugenio Gonzalez (left) and Maldonado (right) stop and question a subject named Devin Maxwell, who is not arrested and receives no summons.

Broken-windows policing first took hold in New York, then spread outward. In the 1990s New York’s brusque Republican mayor, Rudy Giuliani, and his police chief, William Bratton, set out to rescue a crime-besieged city partly by cracking down on petty criminals: graffiti taggers and so-called squeegee men, who swarmed around cars at traffic lights, insisting on cleaning windshields for a tip and sometimes leaving drivers feeling like they’d been mugged.

The city’s new policing also introduced careful record keeping and computerized analysis of crime statistics, precinct by precinct, so that local commanders could be held closely accountable for negative trends and rewarded for positive turns, and so that the department could pinpoint and target precise patterns of lawbreaking. The overarching belief was that cops could make a tremendous difference in the city’s quality of life.

Stop-and-frisk was part of the new regime. It had long had a place in policing, but it began to gain real prominence in the 1990s, accentuated by the pressure on precinct commanders to produce results. Statistics on the use of the tactic dating back that far are scarce, but by 1999, in New York, the practice had become common enough to engender controversy. Early that year, four officers stopped a 22-year-old West African immigrant, Amadou Diallo, outside his Bronx apartment building, thinking he resembled a rapist in a police sketch that had been circulated. From a distance, as he pulled his wallet out of his pocket, presumably to identify himself, the cops thought he was reaching for a gun and fired at him 41 times, killing him instantly. He had no weapon at all. Protests over Diallo’s death led to a state attorney general’s investigation of the NYPD’s use of pedestrian stop-and-frisk—the first thorough analysis of how often it was done, and to whom.

“The real problem is testosterone. In New York City, stops and frisks became ceremonies of dominance.”

The answers were startling. During a 15-month period spanning 1998 and part of 1999, police in the city had made at least 175,000 stops. Blacks (26 percent of the city’s population) accounted for 51 percent of the total; Hispanics (24 percent of the population) accounted for 33 percent; and whites (43 percent of the population) accounted for only 13 percent. Reacting to those numbers, the Center for Constitutional Rights filed a racial-profiling lawsuit against the city, and in 2003 the NYPD settled. It didn’t admit to discrimination, but it did agree to reiterate a prohibition against profiling in a commissioner’s memo to commanders, and to turn over timely data about stops.

None of this constrained what happened on the street. Under Giuliani’s successor, Michael Bloomberg, and his police chief, Raymond Kelly, the numbers climbed year after year: in 2011, the police recorded 686,000 stops. Only about 12 percent of these ended in an arrest or a summons. Between 2002 and 2013, says Donna Lieberman, the head of the New York Civil Liberties Union, “innocent people were subjected to this by-no-means-minor intrusion more than 4.4 million times.”

Meanwhile, though, the city grew far more secure, proving, it seemed, that New York’s mayors and police chiefs were right to have faith in their ability to impose safety. During the past two decades, the rate of what are termed “index” offenses—homicide, rape, robbery, aggravated assault, burglary, auto theft, larceny, and arson—has been cut by 75 percent in New York. These crimes have been largely erased from the city. The change feels almost magical, and suggests something stunning about the possibility of fixing overwhelming societal problems, and of enabling urban metamorphosis.

Inspired by such progress, police departments from Newark to Los Angeles, where Bratton became chief after his tenure under Giuliani, followed New York’s lead, many of them hiring Bratton’s former top brass. Proactive and preventive became terms of art in policing. In Newark, Director DeMaio, a 28-year veteran of Newark’s force (who has just retired), dated the beginning of the surge in field inquiries back to the late 1990s. Comparisons of stop-and-frisk rates are tricky, but my own research indicates that in recent years, the police departments in Newark, Los Angeles, Philadelphia, Chicago, and Baltimore have all rivaled or exceeded the NYPD at its most confrontational.

Because of the lack of statistics tracking the inception and rise of aggressive stop-and-frisk strategies in cities like these, as well as the dearth of probing research into the use of all proactive tactics, it isn’t possible to graph new policies with new levels of safety around the country. And so it isn’t possible to definitively isolate the causes of the 72 percent decrease in index crimes in Los Angeles in the past two decades, the 33 percent decline in Philadelphia, the 54 percent reduction in Chicago, the 55 percent drop in Baltimore, or the 72 percent decrease in Newark. Newark is still a violent city—with a 2013 murder rate almost nine times higher than New York’s—but it has become steadily less threatening than it was in the early ’90s.

Maldonado (left) and Gonzalez (right) check the pockets of two subjects stopped at the corner of Summer Avenue and Elliott Street. The subject on the right receives a summons for public consumption; the other is released without a summons or an arrest.

The 198-page decision written last summer by Judge Scheindlin is the third document worth focusing on if you want to understand the evolution of modern American policing, because it may bring the era of stop-and-frisk to a close. That’s a prospect that worries many in the profession. When I first walked into DeMaio’s office, soon after the ruling, he said he’d just returned from a law-enforcement conference, where the police chief in one of America’s largest cities had asked him in dismay, “What are we going to do about stop-and-frisk?” DeMaio himself was worried about losing the practice. “It would be devastating,” he told me, adding, “The innocent people—they know the reality of living in a city like Newark, and they appreciate that stops are being made.”

Monifa Bandele, an activist with the Malcolm X Grassroots Movement, an advocacy group, has a different perspective. We met in a coffee shop in Brooklyn’s Bedford-Stuyvesant neighborhood to talk about the campaign to end stop-and-frisk. Her father, she recounted, had been a member of the Black Panthers, and two of her aunts had been members of the Student Nonviolent Coordinating Committee in the 1960s. “The movement was my birthright,” Bandele said. She remembered a childhood suffused with “the feeling that one day we’re going to wake up and all this racism around us will be gone.” Such optimism gave way, for a while, to despair, but later it inspired her own activism. In 1999, in a program they called CopWatch, she and other members of Malcolm X Grassroots began driving through some of Brooklyn’s minority neighborhoods, documenting what they felt were unjust stops and other abuses. “The Street Crimes Unit was jumping out on people,” Bandele said. “It was very terrorizing.” After an incident in Harlem, a friend of hers who had just graduated from Cornell became a plaintiff in the racial-profiling suit that was settled in 2003.

Yet 9/11 and the devastating losses suffered by the NYPD, she explained, made it difficult to put pressure on the police. They were heroes and martyrs. And crime was down. There was no way to build momentum for a public campaign critical of cops.

But by 2011 something had changed, perhaps because the number of stops had grown so alarmingly high, perhaps because the city had become tired of its business-mogul mayor, and perhaps partially, one activist colleague of Bandele’s suggested to me, because of the self-questioning sparked throughout the city by Occupy Wall Street. Whatever the cause, an opposition movement coalesced: Malcolm X Grassroots and like-minded organizations banded together, local politicians got behind them, the media started highlighting stop-and-frisk data, and, in 2012, thousands marched from Harlem to the mayor’s home in a Father’s Day protest. In the meantime, the Center for Constitutional Rights launched another lawsuit against stop-and-frisk. The attorneys and advocates together vowed to put the issue near the heart of New York’s 2013 mayoral race. Some would say it became the heart. The winner, Bill de Blasio, ran an ad that featured his son, a mixed-race teenager, promising that his father would “end a stop-and-frisk era that unfairly targets people of color.” It became the political season’s most celebrated TV spot. Udi Ofer, who was the advocacy director of the New York Civil Liberties Union before taking over the New Jersey office last year, was ecstatic. “We couldn’t have dreamed of greater success,” he told me, in an exultant tone that I heard over and over from activists and lawyers allied against the NYPD.

“I have 34 years in this country!” a man in a Mets cap announced when Big Cat approached him. His face was weathered, and he had a lunch box next to him. He looked like a laborer. He’d been sipping Coors with a friend on a splintered stoop when the cops pulled over. The house was boarded up, with a sign reading WE BUY HOMES CASH pasted to the front door.

Big Cat frisked the two men. “I from Cuba,” the one in the Mets cap said. “I’m don’t have freedom in this country?” Millions have felt this same sense of violation. When the cops patted him down, though, they found a folding knife, which he said he carried for protection against black people. The oversize lunch box held only an evening’s worth of booze. The whole situation was difficult to figure out. Maybe the two Cubans were affiliated somehow with the Latin Kings, who had a headquarters up the block. Or maybe this was just a stoop they’d grown attached to for kicking back on Saturday nights.

Down the block on the other side of the street, next to a ragged lot with a couple of vans parked randomly in the undergrowth, was a house the cops knew as a hangout for Bloods. A few streets off, Newark’s immense basilica stood high in the background, luminous. A group of black men sauntered and danced toward the Bloods’ house, blasting a hip-hop anthem that proclaimed, “Nigga, I ain’t worried ’bout nothin’ / Nigga, I ain’t worried ’bout nothin’.” It seemed a vague taunt to the cops, who let it go. The warrant checks turned out negative on the two Cubans. Big Cat kept the knife but didn’t make an issue of it. He wrote the two men summonses for public consumption, and sent them away.

Joshua Rodriguez (left), a junior, and Kiairus Diamond (right), a sophomore, stand in a hallway at the Malcolm X Shabazz High School. Both say they have been stopped and frisked repeatedly in recent months by the Newark police: Joshua 12 times, and Kiairus three times.

Judge Scheindlin’s ruling on racial bias is interesting because of the math it rejects and the math it embraces. Essentially, the NYPD made the case that the racial disparities in who gets stopped are due to the disparities in who commits crimes. The percentage of blacks and Hispanics stopped in New York turns out, in fact, to correspond to the city’s percentage of black and Hispanic index-crime suspects. Many more blacks and Hispanics are naturally going to be questioned, the police maintain. “It’s not racially driven profiling,” DeMaio told me about Newark’s practice. “It’s crime-driven profiling.”

But Darius Charney, the lead trial lawyer for the Center for Constitutional Rights’ suit, looks at the issue very differently. Because 88 percent of the people stopped in New York were innocent, he says, the department was in effect arguing “that law-abiding black people are more suspicious—look more suspicious, behave more suspiciously—than law-abiding white people.” Scheindlin’s decision is grounded in this numerical proof of discrimination. The prejudice may not be willful or even conscious, but in the practice of stop-and-frisk, as Charney frames it, “race is a proxy for reasonable suspicion.”

This situation isn’t made any better by the Supreme Court’s blurry decree half a century ago in Terry v. Ohio, the case that set the standards for stop-and-frisk. To carry out a stop, officers don’t need anything so substantial as probable cause—that’s the requirement for an arrest. But they do need more than just a “hunch,” the justices said. They need “specific and articulable facts” and “rational inferences,” or “acts, each of them perhaps innocent in itself but which taken together warranted further investigation.” And, as the Court stated in a subsequent case, the officer can consider “the totality of the circumstances.” So combine a couple of what the police term “furtive movements”—like walking with your hands in your pockets and glancing over at a police car, things any of us might do—with being in a high-crime area, and you’re subject to a stop.

Maldonado displays two vials of cocaine found during a field inquiry in February.  

The criteria for elevating a stop to the level of a frisk are no more constraining. Technically, you can object at any point in the proceedings, you can question the cop’s rationale, you can even attempt to walk away, but these responses can win you an obstruction charge or the allegation that trying to leave amounts to suspicious behavior. With legal standards like these, there’s a lot of room for factors like race to come into play.

It may not matter enough that a department is well integrated. (The NYPD is more than 40 percent black and Hispanic; Newark’s department, 74 percent.) An abundance of evidence demonstrates that race will come into play for cops, just like it does for any human being. Psychologists who study unconscious bias have shown that no matter what a person’s conscious attitudes, he or she tends to associate black faces with unfavorable and nefarious traits—a finding that holds true, one important study suggests, for about half of black people themselves. If you’re a cop, add to this a daily walk past an all-minority Most Wanted poster in your precinct house, and you’re going to be prone to making some reflexive assumptions.

“Get on the car!”

Kiairus Diamond has heard these words from Newark police on three occasions in the past several months. We talked in the Dream Lounge at Malcolm X Shabazz High School, in the city’s South Ward. Kiairus, a sophomore, sat with Roman Richardson, a senior, and Joshua Rodriguez, a junior. At Shabazz—a school that’s pulling itself up after nearly being shut down four years ago for its dismal test scores and an unsafe environment—the Dream Lounge is a place where a facilitator guides kids to think up projects and life ambitions that might not have occurred to them without some help and space for imagining. The walls are covered in photos of kids declaiming their goals, the floor is carpeted, and there are big red balls to sprawl on while you’re daydreaming. Kiairus, a slightly built, dreadlocked rapper, is now creating a piece of musical theater. “It’s all genres of music,” he explained proudly.

“Get on the car!” means hurry up and spread your hands on the hood or trunk. It means you’d better stay still while you’re frisked. Roman and Joshua have heard it, too: Roman once, and Joshua, in one form or another, 12 times. Neither Kiairus nor Joshua had any record of lawbreaking or trouble at school. Roman was caught in Shabazz a few months earlier with marijuana and was on juvenile probation. He had a job leafleting for one of Newark’s mayoral candidates. He’s more than 6 feet tall and wears his hair in a one-inch Afro. He hopes to be a sanitation worker. His uncle is a policeman.

“Cops in Newark,” Kiairus said, “if your skin is like this”—he touched his dark forearm—“they’re going to think you’re on your way to doing something, or coming from doing something.”

“When I see the cop car pull up,” Joshua said, “it’s confusing and infuriating.”

“It’s racial profiling,” Kiairus said.

Gemar Mills, the principal of Newark’s Malcolm X Shabazz High School, adjusts the blinds in his office. 

I spoke with Shabazz’s principal, Gemar Mills, in his office. He wore a cardigan in the school colors, black and gold, with the Shabazz crest beside the buttons. Behind his desk hung a giant school banner. “It reduces your self-confidence,” he said of stop-and-frisk. “It’s no different than getting robbed. Getting put up against a wall, it’s no different than someone stealing your stuff. It can be traumatizing. For the police, they let you go, it’s no harm, no foul. But it can make children feel the community has given up on their chance to be successful.”

Mills has taken the school from a 19 percent passing rate on the state math exam to 37 percent. The situation at Shabazz was so bad before Mills took over, in 2011, that Newark’s Star-Ledger once likened the school to Baghdad. His shoulders are broad. He played college football. As a teenager, before sports straightened him out, his life had been going awry; he wound up with 400 stitches in his face after friends started “some trouble in a club.” The scarring is somewhat hidden behind his beard. “I grew up in the projects,” he said. “My mother had me when she was 16, my father said I wasn’t his. I’m not supposed to be sitting here in this office; I’m not supposed to be getting my doctorate. The labels don’t always apply. But the labels affect the amount of stop-and-frisk that goes on in these neighborhoods.”

He was thinking of his students, but he has firsthand experience. This past December, he was driving near Shabazz and spotted a kid who’d dropped out. He called the boy over to his SUV, chatted with him through his open window, encouraged him to come back to school, and continued on his way. Within seconds, cops in a squad car came up behind Mills, pulled him over with a whoop of their siren, asked for his ID, and told him to open his back windows so they could peer inside. Only once he’d calmly convinced them that he was Shabazz’s principal did they say he was free to go.

Maldonado straps on a bullet­ proof vest at the start of an overnight patrol of the city’s Second Precinct.

Has stop-and-frisk brought any benefits? Scheindlin did not consider this question in her courtroom. In fact, she scolded the NYPD for raising it. Her job was to determine the constitutionality—not the efficacy—of policy and actions, and she sent a loud message, heard around the country, that the department’s strategy fell on the wrong side of the law. Yet the answer to the question—which civil-rights advocates don’t much like to hear—is probably yes.

Ever since the 1990s, as crime rates have tumbled in New York and diminished nationally, liberal camps have been loath to allow that the improvements have much to do with policing. This stems partly from an aversion to Mayor Giuliani, who would have to get some of the credit if credit were to be given. It stems, too, from long-held liberal uneasiness, even antipathy, toward law enforcement. Rather than praise human intervention, many liberals have tied the era of increasing safety, especially in New York, to impersonal trends, from demographic and socioeconomic patterns to the decline in the use of crack cocaine.

Nobody has studied the trends and the numbers more thoroughly than Frank Zimring, the chair of the Criminal Justice Studies Program at the University of California at Berkeley. Once you get him talking about the statistics he’s gathered, it’s hard to get him to stop. “I was and am a law professor who voted for McGovern,” he said when I asked about his politics. “So I come to all this with ambivalence. But I am moved, as a scientist.” Then he started in on his charts and tables.

In 2012, Zimring published The City That Became Safe: New York’s Lessons for Urban Crime and Its Control, in which, drawing on an unsurpassed wealth of data, he tries to isolate the causes of the crime drop in New York, particularly after 2000. In doing so, he debunks all sorts of liberal claims. To begin with, he reveals that the demographic argument—which rests on the idea that New York’s population has collectively aged beyond its worst crime-committing years—doesn’t stand up. Yes, the city’s overall population is slightly older, but to concentrate on the racial groups responsible for the huge majority of index offenses is to discover that the percentage of blacks and Hispanics between the ages of 15 and 29 hasn’t decreased at all since 2000, even though crime has gone right on declining. As for the notion that falling crime rates can be linked to the availability of legal abortions beginning in the 1970s, and to fewer boys growing up in troubled, single-parent homes, Zimring assembles data showing that the number of children raised in single-parent households has climbed in the decades since 1980.

But what about New York’s economic boom? What about gentrification? Since poverty is the root of crime, aren’t these factors behind crime’s abating? Zimring lays out the figures. Poverty counts have remained stubbornly high; so has youth unemployment. (If anything, the ever-widening gap between the city’s rich and poor should lead to deeper feelings of alienation and more lawbreaking.) Maybe if New York consisted only of Manhattan, from where the impoverished have been displaced, the economics could explain the trajectory of crime. But turn to Brooklyn, the Bronx, and Queens, where index offenses have plummeted about as much, and economic answers don’t hold up.

Maldonado searches for drugs and weapons outside an abandoned house.  

Incarceration rates? No, the incapacitation of criminals can’t be the cause, because over the past two decades the rate of New Yorkers sent off to prison has dropped by 40 percent.

What about the end of the crack epidemic? Again, no. That came in the mid-1990s. It doesn’t correlate well with the crime graphs.

What does correlate strongly is proactive policing. But is it possible to separate out the elements of this kind of law enforcement—to discern whether, say, arresting petty criminals like squeegee men, or holding local commanders strictly accountable, or stopping and frisking on the street, is the most important, or whether all are necessary?

About a year ago, amid the media firestorm leading up to Judge Scheindlin’s ruling, the NYPD hurried to curtail stops. By the final months of 2013, the frequency had dipped well below the rate that led to the initial lawsuit back in 1999—though Zimring notes that wiggle room in record keeping could lie behind some of the statistical shift. No rush of crime has followed, which activists cite as proof that the tactic is an unnecessary evil. But others caution that the time frame is too short to clarify anything. There’s also the possibility that with crime in New York so attenuated, aggressive measures have become less crucial.

Zimring, for his part, is certain about the effectiveness of the proactive package. “Stopping people you don’t trust is an essential ingredient,” he says, adding, unapologetically, “It is part of owning and governing the territory you’re patrolling.”

Less clear is how much stopping and frisking police should do, and how it should be done. “There are a lot of stops in any good big-city police department,” he says. “The real problem is testosterone. In New York City, stops and frisks became ceremonies of dominance. The tactic is invasive, inherently. It is degrading when it’s done wrong, when it’s testosterone-laden … What I don’t know is if  … the dominance in those stops and the sheer volume of them were essential to the results.”

When we talked, Zimring wanted to make another thing plain. No stop-and-frisk strategy of any value, he said, was going to look “democratic.” As long as departments zero in on high-crime areas, as they should and do, cops are going to be patting down a preponderance of young minority men, some guilty and some innocent. And minorities—who are the preponderant victims of index crimes, the people most often killed and mugged and burglarized—are going to be the most immediate beneficiaries. This benefit, Zimring argues in cold terms, comes with a price, “a special tax on minority males.” And that leads him to ask whether the awful emotional cost can be reduced while the benefit is retained.

A subject is frisked in Newark, New Jersey. No illegal materials are found.

Monifa Bandele has a simple reply to this kind of rumination. Stop-and-frisk, she insists, should be abolished. “The idea that cops need to intimidate people of color, to violate our rights in order to protect people of color,” she says, “is like some Islamist societies’ saying the only way to protect women is to keep them under Sharia law.” It would be acceptable, she told me, to stop pinpointed suspects of specific crimes—but what she was outlining has little to do with proactive street policing.

The positions of civil-rights lawyers around the country may not be quite as absolute, but in 2012, when San Francisco Mayor Ed Lee discussed policing with Mayor Bloomberg and then announced that he was contemplating a stop-and-frisk policy to combat gun violence, local attorneys and advocates and the Center for Constitutional Rights raced in to make sure Lee reversed himself. In New York, meanwhile, a curious thing has happened. The new mayor, who ran so ardently against stop-and-frisk, has named William Bratton, the architect of the city’s aggressive tactics in the 1990s, as the new police commissioner. In ways yet to be spelled out, Bratton will have to attempt to soften policing while making the city ever more secure.

When I rode with Big Cat and Gesuelli, many of their judgments about the people they decided to stop, biased or not, were on the mark. Their track record suggests two lessons. One is that the tally of innocent people waylaid, as calculated by civil-rights attorneys, isn’t completely accurate. That is, it’s legally precise but at the same time misleading—a complexity that underscores the challenge of policing in accord with fundamental rights and in the hope of criminal deterrence. Cops may come up empty and let a subject go without an arrest or a summons (as happens 74 percent of the time in Newark), but this doesn’t always mean that they’ve targeted a law-abiding citizen. Take the pair of black men Big Cat and Gesuelli stopped on a rough block during our rounds in the Second Precinct. One was sitting in a parked car, the other was leaning into its passenger-side window.

“When was the last time you were locked up?,” Big Cat asked the two men.

“Four months,” one of them said.

“For what?”

“I don’t know. Narcotics. Something.”

“You don’t know?”

“It was heroin.”

“How much heroin?”

“I believe it was 83 bags. But that don’t mean I couldn’t change my life around.” He didn’t sound altogether earnest.

It wasn’t the only time I heard this kind of conversation. Another man, wearing ski pants and sitting on a parked car on a dark street, told the cops that he had 12 felony convictions and had done federal time on a gun charge. “I’m just waiting on my mom,” he said when asked why he was perched on the car hood in ski gear. Frisking him, Big Cat found only some empty mini ziplock baggies in a breast pocket. “What are these for?”

“Paperwork.”

The second lesson is more hopeful. What if cops were heavily trained to be careful in their judgments, and to do their field inquiries with respect and even a measure of deference? My nights with Big Cat and Gesuelli—who rarely raised their voices—suggest that such a change might be feasible. The idea may sound a little naive, but it comes up often in discussions about stop-and-frisk. Zimring brought it up during our conversations. “Why couldn’t it work?” he asked. “Why not remove the testosterone? Why not Stop-and-Frisk Polite? Why not a different kind of policeman?”

In Shabazz’s Dream Lounge, I asked the three teenagers about how they thought stop-and-frisk might be improved.

Kiairus, the musical-theater writer, said, “People skills.”

“Don’t just jump out of their car,” Joshua advised. “Say ‘Excuse me.’ Ask me. A little more polite.”

Roman, the would-be sanitation worker, grimaced. “Ain’t no cop going to say, ‘Sir, may you pleeease empty your pockets?’ ”

I posed a more general question. You’re the police director: What would you do about stop-and-frisk?

“It’s not cool,” Kiairus said. “I don’t think they should do it at all.”

“I think the whole stop-and-frisk thing is kind of bad and kind of good,” Roman said.

Extending the hypothetical, I asked them what they would tell me if I were a rookie cop. Smiling minimally, painfully, Roman said, “I’d tell you to look for black people. We’re the reason this happens. Think about it. The main people who are locked up, wind up dead, or are doing nothing with their life—it’s black people. It’s not just a stereotype. We’re committing most of the crimes. We do dumb things, rob stores, kill our own friends.”

This was one of the more wrenching things I heard during my time in Newark, and it reminded me of what a 28-year-old named Corey France had told me. He lives in the West Ward, works in an auto-parts warehouse, and has no record. He’s been stopped and frisked, but he doesn’t like recounting the incident. “It’s uncomfortable to speak about,” he said. “You feel ashamed. I feel like even talking about it brands me as a criminal.”

His words echoed what Principal Mills had described: the way stop-and-frisk can ravage self-confidence. But despite all its problems, Mills emphasized to me that he isn’t thoroughly opposed to the policy. “I think there’s value there,” he said. “Maybe a gun gets off the street, a life gets saved, maybe drugs get confiscated—that’s the pro. But then there are the side effects.”