David J. Thomas grew up in Detroit in the 1960s, two blocks from the headquarters of the 10th Precinct. Nighttime echoed with .50-caliber machine guns. Mornings dawned over neighborhood rubble. Thomas remembers being 11 years old, approaching a squad car outside the corner store and asking a police officer how fast it could go. The officer stuck a nickel-plated handgun in his face and said: “It goes fast. Now get away from my damn car.” Thomas remembers being 12 and pulling a wagon full of newspapers down the street to help friends with their paper routes. Officers in a nearby squad car rounded up the friends, searched them, asked for IDs and told them it was against the law to walk in the street. Thomas remembers being in middle school and the police hauling him and his friends into alleys to rough them up for sport. Thomas remembers being 19 and being followed by an unmarked car from the basketball court to a friend’s house, where police drew shotguns and ordered him facedown in the snow because a black suspect had just committed armed robbery somewhere else.

And he remembers being 22 and telling his father that he himself was going to become a police officer. It was a decent job in public service, in a city dying with the auto industry: a $20,000 salary and the chance to be out in the community.

His father was furious. He hated the police for the way they treated black people, Thomas says, and was convinced the racism of police culture would corrupt his son.

“What he saw standing before him was 60 years of his life, me becoming something that he did not trust and someone that my community would hate,” says Thomas, who spent 20 years in law enforcement and is now a mental health counselor working with police officers in Gainesville, Fla. “His greatest fear was that I would become a traitor.”

This is the struggle of black police officers, then and now. They sign up for a job that offers a path to a middle-class life and a chance to honor their communities by pledging to protect them, but they can face questions of loyalty from neighbors who are skeptical of law enforcement. They want to “be the change,” then realize what they’re up against: a police culture with a legacy of prejudice, protected by unions, resistant to self-examination and primed to use force.

That culture is now under a microscope. On May 25, George Floyd, a black man, died after white Minneapolis police officer Derek Chauvin knelt on his neck for nearly nine minutes, in full view of citizens and their cellphone cameras, as well as three fellow officers — one white, one black and one Asian American — who have since been fired and charged in connection with the killing. Videos from that incident sparked an explosion of protests against police brutality over the past month. In instances across the country, police have responded to protesters with chemicals and violence.

Black Americans have endured this type of force and oppression for generations. Some became police officers anyway. From the video of Floyd’s death, many feel fresh horror and an old dread.

Police officers “beat up my brothers,” says Rochelle Bilal, who grew up in North Philadelphia in the ’60s and ’70s. “We thought they were the occupied enemy in my neighborhood. We’d be up on the roofs throwing stuff down at them. We saw nothing good from them.”

In 1986, at age 29, she decided to follow a local officer’s advice and be the change she wished to see.

“But how could I know, when I walked into the door,” Bilal says, “that I had not really understood racism, and disparity in treatment, until I was in the police academy?”

As a recruit, Bilal saw white officers escape formal discipline while black officers were punished for similar infractions. On patrol, she would pull up and hear other officers saying, “Aw, dang, here’s Angela Davis.” In 2009, as a veteran, she saw an online message board for city police — under the banner of “the voice of the good guys” — become a bulletin for obscene racial remarks such as “ghetto monkey faces.”

Now, at 63, Bilal is the sheriff of Philadelphia. She is a black woman protecting a major U.S. city while grappling with a major cultural problem. She was an early advocate for a Pennsylvania bill banning chokeholds. And if she had been on the scene in Minneapolis in May, when Chauvin put his knee on Floyd’s neck?

“Those of us who are conscious cops, we would have knocked his butt, and there would have been a fight on the street: cop on cop,” she says. That kind of intervention is not inevitable, however, even when officers are conscious of the dangers of abusive policing. One of the officers charged with aiding and abetting Floyd’s killing is a young black man, on only his third shift, who had hoped to help fix police culture from the inside, his mother told the New York Times. At a June court appearance, the young officer’s lawyer told the judge that during the encounter with Floyd, his client told his colleagues , “You shouldn’t do this,” and tried to “communicate that this situation needs to change direction,” to no avail. Contacted last week by The Washington Post, the lawyer declined to elaborate.

It’s “the black and blue conundrum,” which is what John Q. Williams might title the book he’s working on. Williams came of age in Gary, Ind., in the ’80s and ’90s, when the demographics of the police force did not reflect the community. He remembers white police waiting around with handcuffs after football games in the black community and being pulled over as a teenager while driving his mother’s sleek 1989 Buick Riviera because officers wanted to “check the insurance.”

Last month, Williams won the Democratic primary in the race for sheriff of Athens-Clarke County in Georgia. Part of his platform is requiring “bias in policing” training for all new deputies and nurturing a culture of “radical transparency” that admits to its mistakes.

“There are people who force things on you as a black man, and there are things they force on you as being an officer,” says Williams, a sergeant and instructor for the county police department’s career development and training unit. “Then you have family and media and people telling you, ‘These things clash and you can’t be both’ or ‘You’ve got to be more one than the other.’ That’s not true. When you’re a human being, and you’re doing this for the right reason, you just do it.”

But sometimes, doing right means running afoul of your own department. In 2006, a black police officer in Buffalo named Cariol Horne physically intervened when a fellow officer, who was white, was choking a handcuffed black man. There was no video of the incident, and other officers did not corroborate her account. Horne, who is black, was fired, just short of 20 years of service that would have allowed her to draw a pension. The white officer was eventually terminated for a pattern of abusive behavior, and an FBI investigator criticized the Buffalo Police Department for having a culture that permitted misconduct and excessive force.

On June 4, during a protest of police brutality, two white Buffalo officers appeared to shove a 75-year-old protester to the ground, fracturing his skull. The department initially claimed that the man, who is also white, “was injured when he tripped & fell” — a description that stood in stark contrast to a video of the incident. After the video was posted online by a local radio station, the officers were charged with assault.

Two days later, Horne was outside the Erie County District Attorney’s Office in downtown Buffalo, as members of the police union and their supporters gathered to applaud the officers who were charged. Horne wandered the crowd with a megaphone, recording and narrating the scene on her phone, trying to spotlight an aspect of police culture that some white people are just waking up to. Attendees jeered her, calling her a “traitor.” Men tried to block her view with their bodies and held up fabric to create a wall against both the media and Horne’s dissent.

“This is what they do when they kill us,” Horne said to her phone as she captured behavior that was both literal and symbolic. “They come and they cover it up.”

Across the country, there are about 18,000 law enforcement agencies. The most common are small-town police departments with 10 or fewer officers. Culture varies. But there are consistencies when it comes to race and the perception of race. In 2016, black officers made up about 11.4 percent of the full-time ranks in local police departments. (The U.S. population was 12.6 percent black that year.) But in urban areas, police are much whiter than the people they serve. And in 2016, a whopping 92 percent of white police officers said that the United States had already made the changes needed to give black people equal rights with white people — a view shared by only 57 percent of white people in general, according to a survey by the Pew Research Center. Almost 70 percent of black officers, and 84 percent of black people generally, said that changes still needed to be made.

Of course, there is a range of attitudes in every police unit, and some white officers have expressed solidarity with the Black Lives Matter movement. And plenty of change is visible if you stick with a police department for decades. Robert Contee grew up in the Carver-Langston area of Northeast Washington — riddled by crime in the 1980s and referred to as “Little Vietnam” — and started his career in law enforcement as a high school cadet during the city’s crack epidemic. Contee saw police officers, grappling with drugs and homicide, degrade the community and rely on excessive force.

“This is not the department I joined 30 years ago,” Contee says now, as an assistant chief of the District’s Metropolitan Police Department. “It doesn’t resemble it in any shape, form or fashion. I think we’ve gotten smarter about things, in terms of the way that we deal with the communities that we serve. We’ve learned that you can’t arrest your way out of problems.”

Two years ago, D.C. police began enrolling every recruit in a 10-hour curriculum at the National Museum of African American History and Culture.

“Officers coming here need to understand not just the city, but the people in this city,” Contee says.

But prejudice and hate can still percolate beneath the surface. Since 2017, an online database called the Plain View Project has gathered and published thousands of racist and Islamophobic posts by confirmed police officers in eight U.S. cities. In Wilmington, N.C., three officers were fired in June for using racist language that was recorded on a patrol camera.

“We are just gonna go out and start slaughtering them f---ing n-----s,” said Michael K. Piner, a 22-year member of the Wilmington Police Department, using a racial slur while complaining about recent protests against police brutality and envisioning a civil war or martial law. “I can’t wait. God, I can’t wait.”

What if Piner’s camera hadn’t been accidentally activated? What if the audio had not been found during a routine audit by a sergeant? Piner’s fellow officers had not reported his remarks.

“The blue code of silence — and the blue code of wanting to be accepted by your peers — is juvenile,” says Heather Taylor, a homicide sergeant in St. Louis. But it persists.

Loyalty is a hallmark of police work — on display whenever officers drive across the country to pay respects to their fallen brothers and sisters. The occupation’s shift work, with long hours and heightened levels of risk, engenders that loyalty; powerful unions help enforce it. And officers seen as not sufficiently loyal to their colleagues can pay a steep price.

As head of the Ethical Society of Police, a watchdog group founded by black officers in 1972, Taylor says that she has made a point of calling out silence and misconduct and that fellow officers have responded by calling her a “c---” and “b----.” Even in the short time since the death of George Floyd, there has been racial friction in her police department. She says one dispatcher wore a shirt that said “Can’t Breathe? Don’t Commit Crimes,” and another referred to protesters as “animals.” A board member of the Ethical Society of Police found a note in his files that said, “Hitler rules.” (The incidents are being investigated, says a spokesman for the St. Louis Metropolitan Police Department.)

At a June 22 news conference in St. Louis, members of the Ethical Society of Police repeated their wish for mandatory cultural competency and bias training for all ranks in the department. While such trainings are being instituted in departments across the country, changes won’t be institutionalized if the institution itself is wired against them.

“Behavior is more likely to conform to culture than rules,” stated the 2015 report from President Barack Obama’s task force on 21st-century policing.

Or, as Taylor puts it: “Police culture will eat policy and procedures for breakfast, lunch and dinner.”

The roots of modern policing go all the way back to slave patrols of the antebellum South, according to historian W. Marvin Dulaney, which had unrestricted power over enslaved people and often used violence. After emancipation, law enforcement maintained racial control for generations — up to and including today. “The only difference between the policing that Africans Americans have experienced since slavery and now,” Dulaney wrote in 2015, “is that it has been documented and recorded by cell phone cameras.”

After the Civil War, when black people were allowed to join the force, it wasn’t for the sake of diversity. “It was, ‘We can do a better job keeping an eye on these people if we have one in our ranks,’ ” says Khalil Gibran Muhammad, a professor at the Harvard Kennedy School and author ofThe Condemnation of Blackness: Race, Crime, and the Making of Modern Urban America.”

Black officers were allowed to police only black communities, Muhammad says, but “they saw themselves as different from their white counterparts. They saw themselves bringing community knowledge and cultural connection as a form of trust-building.” And on a personal level, they sometimes succeeded, Muhammad says, though their efforts were often undermined by the actions of racist colleagues. And it wasn’t just white colleagues acting with prejudice; some black officers also behaved in racist ways toward members of the black community.

The efforts of what Bilal called “conscious cops” are still being undermined by those who discriminate. White officers use higher levels of force, specifically against black men, according to the research of Eugene Paoline, a professor of criminal justice at the University of Central Florida. Black officers used the same level of force, regardless of the race of the citizen they were arresting.

Law enforcement needs “a national minimum use-of-force policy,” a prohibition on chokeholds and mandatory de-escalation training, according to Cerelyn J. Davis, the police chief of Durham, N.C., and president of the National Organization of Black Law Enforcement Executives.

“As an African American woman, I can unequivocally attest to the perpetual existence of discriminatory practices that remain a haunting reality for people of color throughout our nation,” Davis testified before the Senate Judiciary Committee on June 16. We need to “urgently begin the process of reimagining today’s police culture” and enlist “guardians and not warriors” as police officers.

Heather Taylor of St. Louis echoes the guardian-versus-warrior issue. Police culture has an ego problem, she says, which can intertwine with its race problem. She points to the video of Rayshard Brooks, a black man shot by a white officer after taking a Taser during a scuffle June 12 in Atlanta.

“Brooks got the better of two officers, and I know it was embarrassing because it’s on video,” Taylor says. Police officers, she says, “will talk about each other to no end. ‘You let someone take your Taser? You have no business in this job.’ When that person turns that same Taser on you, you think, ‘I’ll shoot them’? That was about ego.”

David J. Thomas, the retired officer who’s now a counselor in Florida, has been thinking about Derek Chauvin, the Minneapolis officer who knelt on George Floyd’s neck before his death. He watched the videos of Chauvin kneeling on his neck and saw the problem of police culture in Chauvin’s face — as he registers that his actions are being documented.

“He’s looking at the kid who’s videoing him on the phone,” Thomas says, and “he was comfortable in that. That meant to me that he had done this a thousand times before. And he was supported by the organizational culture in the union, and he would not get in trouble.”

Now, Chauvin is a former officer charged with murder. The chief of Minneapolis’s police union has said his firing was justified. A couple of weeks ago, Thomas, now also a forensic studies professor at Florida Gulf Coast University, visited his former employer, the Gainesville Police Department, and saw different looks on the faces of the officers there: expressions of stress and frustration. They were worried about making honest mistakes, he says. They worried about choosing to do the right thing, procedurally, but getting pilloried by the public.

Does this mean change? Thomas prays that Floyd’s death will help change police culture, but he says it will happen only if first-line supervisors in local departments submit to — and enforce — accountability. “It needs to be understood,” he says, “that the cultures of law enforcement agencies are deeply entrenched and begin with the academy.” For all the piecemeal changes, the gradual diversification of the ranks and the elevation of black officers to positions of authority, he doesn’t think things have really changed since he was a rookie. “The culture is exactly the same,” he says. “It’s not just white officers guilty of this stuff. Black officers are guilty. It is the blue line.”

He believes there was wisdom in his father’s warnings, all those years ago. “I would say that what he was right about was the culture of policing,” Thomas says. “The need to be accepted by your peers and to what lengths will you go to be accepted. What he didn’t know is that every officer has to modify their behavior to be accepted by the culture.”

Martesse Gilliam’s father was an officer, and to Gilliam, he was a hero. So at age 23, Gilliam followed in his footsteps and joined the force in Plainfield, N.J. Less than two years later, in 2010, while he was off duty, someone spat into his car outside a nightclub in nearby Bloomfield, he says. Gilliam says he sought the help of a police officer in the parking lot but was arrested instead. He was handcuffed. Officers bashed his head into a patrol car, he says, and slammed a car door into his shins. Then, he recalls, he was on the ground, a boot on his head. Officers punched and pepper-sprayed him.

“I felt that my dignity was taken away,” Gilliam says of his arrest and the subsequent hours he spent sitting in the police station. “I felt like less of a human. I felt inferior to the white officers who were there.”

Eventually, a jury found Gilliam not guilty of assault on an officer and resisting arrest, though a trial judge did find him guilty of driving while intoxicated. Gilliam, who testified that he had three drinks that night, still denies the charge. He sued the township for excessive force. The case was settled. Gilliam tried, for several years, to go back on the job and do the work he once considered heroic, but he couldn’t square his idealistic view of policing with the treatment he experienced. Today, he runs a fitness studio that integrates boxing, yoga and meditation.

“I felt like I had no control,” Gilliam says of the trauma. “Like it doesn’t matter who I am. Doesn’t matter how far I might be promoted in the police force. Doesn’t matter how much money I may have or earn. At some point, when faced with white police officers who don’t know who I am, I’m going to possibly be just looked at as a criminal — and my life can be taken away.”

Last month, Gilliam brought his three children to a march in New Jersey to demand an end to police brutality. His father, now retired, joined them.