Despite furor, accountability lags for police. Here’s why it might change.

It’s not his phrase, but former Seattle police Chief Norm Stamper covets it when describing police officers: “tiny principalities of power.”

Armored with immunity for a wide swath of behavior, protected by unions and friends and demands for civic order, and beholden more to a beat cop code than to the chief’s orders, the 900,000-strong American police force cuts a unique profile: They aren’t mentioned in the U.S. Constitution.

On even the best day, officers say, they have immensely difficult and dangerous jobs. Nearly every social problem is theirs to deal with, to the best – and sometimes worst – of their abilities.

“The power of that institution to shape behavior of so many police officers is almost to the point that supervision and management and leadership seem not to count,” says Mr. Stamper, author of “To Protect and Serve: How to Fix America’s Police.” “What really counts is the opinion of your fellow cops on the beat. It is in fact axiomatic that the structure produces this culture and that culture gives rise to behavior.”

Hardly alone, Mr. Stamper is wrestling with how that blue wall contributed to four Minneapolis police officers committing what he considers the murder of George Floyd, kneeling on his neck despite pleas of help from the man and bystanders. On Friday, former Officer Derek Chauvin was arrested and charged with third-degree murder and manslaughter.

To be sure, their near-immediate firing was “unprecedented” and warranted, says Mr. Stamper.

Major city police chiefs have decried the killing of Mr. Floyd, calling it “deeply disturbing” and “of concern to all Americans.” That swift denunciation, rather than silence and circling the wagons, might be one early glimmer of progress in a problem that data shows has not budged over the past five years – despite widespread outrage, the efforts of the Black Lives Matter movement, and large-scale protests across the country.

“The role that we have come to depend on officers to play in society makes it difficult to criticize or reform what they do,” says Seth Stoughton, a former police officer from Tallahassee, Florida. “They don’t deal with a particular problem; they deal with every problem. So it’s hard to say, ‘Oh, by the way, change what you’re doing here.’”

The U.S. Department of Justice is among several jurisdictions looking into whether crimes were committed. Meanwhile, some Minneapolis neighborhoods have descended into chaos as the killing unleashed protests, riots, and looting. A police precinct was burned Thursday night.

On Thursday, Hennepin County Attorney Michael Freeman said that he didn’t want to participate in a rush to judgment. “We have to do this right. We have to prove it in a court of law,” he said. “I will not rush to justice.”

“In this case, it’s good that they have a video because otherwise there would be no trouble for the officers,” says David Harris, author of “A City Divided: Race, Fear and the Law in Police Confrontations” and a professor at the University of Pittsburgh School of Law. “And at least they got fired. But there’s no guarantee of anything else. The law is slanted in favor of police.”

Indeed, research into police culture and behavior underscores the seemingly unbending struggle to hold lawbreaking officers to account.

“It does ‘feel’ like we are seeing more of these cases [of officers being adjudicated], but actually we aren’t,” says Bowling Green State University criminologist Philip Stinson, who tracks officer convictions, in an email.

The struggle to balance the law with the order is a fundamental one in the modern United States.

In order to limit frivolous lawsuits, the U.S. Supreme Court has expanded the ability of police to use excessive force by expanding qualified immunity, which forces juries to answer two chief questions: Were officers breaking “clearly established law” and were they aware that their conduct was illegal?

Police won 56% of cases in which they claimed qualified immunity from 2017 through 2019. That was up from the three prior years, when they won 43% of the time, a Reuters investigation found.

In one case near Dallas, five police officers fired 17 bullets and killed a bicyclist in a case of mistaken identity. A court threw out a lawsuit on grounds of qualified immunity. A cop who shot and killed a fleeing suspect through his windshield from a bridge was found justified for the same reason.

In South Carolina, a jury couldn’t come to a verdict in a case where an officer was filmed shooting a fleeing man named Walter Scott in the back and then planting a Taser to make the shooting look justified. The officer, Michael Slager, is only serving prison time due to a plea deal to avoid a federal trial.

In Chicago, Jason Van Dyke was found guilty in 2018 of second-degree murder for the killing of Laquan McDonald in 2014. Three other Chicago officers were acquitted on charges of covering up the murder.

Such legal twists underscore how “as a society we often give contradictory guidance to police officers about what their role should be: ‘We want you to be hard on crime, but also respect everyone’s rights,’” says Mr. Stoughton, co-author of “Evaluating Police Uses of Force.” “That’s difficult to mesh.”

Even when police departments do fire officers with a record of misdeeds or unprofessionalism, there are few guarantees they’ll stay off the beat – even rising to the top of the profession.

Last year, USA Today showed that 32 officers convicted of various levels of misconduct, with at least eight found guilty of a crime, were let go, before finding their way to the top as chiefs or sheriffs. What’s more, thanks largely to states with strong police unions that provide fired cops with arbitration, 30% of such cops are reinstated with back pay.

The officer who killed 12-year-old Tamir Rice in Cleveland lost his job, but was hired by a small-town department in the region.

In the case of Eric Garner, a New Yorker who died after pleading with an officer to release a chokehold, the officer was eventually fired. He is now seeking reinstatement with full back pay.

Minnesota recently saw its first officer convicted and imprisoned – for killing a white Australian American woman, Justine Damond, in 2017. Mohamed Noor, the former officer, is of Somali descent. But the Midwestern state also saw a jury acquit another officer for shooting Philando Castile, who was black, during a traffic stop for a broken taillight. Jeronimo Yanez, the officer, is of Hispanic descent.

Painfully, America’s long history of racial violence colors those charts.

2019 saw the largest number of deaths by police, with over 1,000, according to a Washington Post database. Black men are twice as likely to be shot by police – a number that has not budged since uproar began over killings with the death of Michael Brown in Ferguson, Missouri, in 2014. In the U.S., being killed by an officer is one of the main mortality risk factors for younger black men.

“Many police officers have a tendency to prioritize human life and to somehow, probably on a subliminal level, make tactical decisions based on the color of someone’s skin, such that black people in America are at much greater risk for instances of excessive force,” says Mr. Stamper in Seattle. “There’s no way to pretty that up.”

Yet progress can be measured in small ways in a country with 18,000 police departments, each a fiefdom.

Reformers are pushing to strengthen decertification programs that make it difficult for troubled officers to reenter the profession. Some 30,000 cops in 44 states have been decertified since the 1960s.

A program called EPIC (Ethical Policing Is Courageous) that protects junior officers when they speak up against the actions of more senior officers has led to spikes in community approval for police in cities like New Orleans. EPIC connects officer welfare not to outside demands, which cops often shrug off, but the need to protect a fellow officer from making a career-ending mistake.

What’s more, the U.S. Supreme Court could announce Monday whether it will consider a case that could define whether police and other deputized officials deserve qualified immunity as protection against lawsuits.

And even if cellphone videos don’t guarantee convictions, the moral clarity they capture can be crucial.

On Thursday, the Kansas City Board of Police Commissioners announced that the city would start using the video of Mr. Floyd’s death to train officers how not to detain a suspect. (Police training manuals, including one by Mr. Stoughton, forbid the use of body weight on the neck as a restraining tool, as happened to Mr. Floyd, because the maneuver can kill.)

And for at least one Minneapolis area officer, the incident was cause to grieve and talk with fellow officers – and black and white members of the community.

“We live in two different worlds and no matter what I’ve done while I’ve worn this uniform, this has not changed,” Officer Justin Pletcher wrote in a Facebook post that he gave the Monitor permission to quote. “I may have changed moments but I have not changed the world like I thought I would.”

Such introspection on the part of both police and the communities they serve is vital, experts say.

“If we don’t absorb that [race can be weaponized], and all try to change and do things differently, we’re going to be stuck with this problem for a long time,” says Mr. Harris.