Daniel Shaver, 26, was unarmed. He was sobbing, begging the police officers not to shoot him. He was crawling on the floor toward officers, as a cop on the scene told him to do. But as he inched forward, he appeared to extend his hand backwards — and an officer, 27-year-old Philip Brailsford, opened fire, killing Shaver.

On Thursday, Brailsford was acquitted of a murder charge over the 2016 shooting. Police then released video of the encounter.

The video footage, taken from Brailsford’s body camera, begins with Mesa, Arizona, police officers intercepting Shaver and a friend outside of their hotel room, where officers responded following a report of someone pointing a gun out a window. The officers are very aggressive from the start, warning Shaver and his friend that they will be shot if they disobey any orders.

“If you make a mistake, another mistake, there’s a very severe possibility that you’re both going to get shot,” Charles Langley, a since-retired police officer, said. After they both responded, Langley said, “Shut up. I’m not here to be tactful or diplomatic with you. You listen, you obey.”

The situation progressed from there.

“Young man, you are not to move,” Langley said. “You are to put your eyes down and look down at the carpet. You are to keep your fingers interlaced behind your head. You are to keep your feet crossed. If you move, we are going to consider that a threat, and we are going to deal with it, and you may not survive it. Do you understand me?”

The woman with Shaver was then directed to crawl toward the officers, which she did. After, Langley asked the same of Shaver. A clearly terrified, sobbing Shaver began to move to comply. The officer shouted at him. “Please do not shoot me,” Shaver said. He began to crawl.

But when Shaver’s hand moved toward what appeared to be his waistband, Brailsford opened fire. Brailsford said he believed Shaver was reaching for a gun.

The Associated Press and CBS News reported that the detective who investigated the shooting agreed that it could look like Shaver was reaching for a gun, but it also just looked like Shaver was trying to pull up loose-fitting gym shorts that had fallen as police ordered him to fall to the ground and crawl. The investigator also noted that there was nothing, based on the evidence, that should have stopped the officers on the scene from handcuffing Shaver while he was on the floor.

On trial, Brailsford testified that he fully believed that Shaver was reaching for a gun. Shaver ended up having no gun on him, but police found two pellet rifles in his room, related to Shaver’s pest-control job.

Brailsford said he would make the same decision again. He claimed he felt scared for the safety of officers and the woman in the hallway.

The perceived threat was apparently enough, based on existing legal standards for police use of force, for Brailsford’s acquittal. By reasonably perceiving a threat when Shaver reached for his waistband, even if Shaver did not actually have a gun, that was enough for Brailsford to legally justify the shooting.

Brailsford, a two-year veteran of the Mesa police force, was previously fired for department policy violations, including unsatisfactory performance.

Shaver, like Brailsford, was white. But the shooting has drawn criticism from Black Lives Matter activist Shaun King, who said it was yet another example of police brutality in America. He argued on Facebook, “After you watch this video, which is horrible, you will wonder how the officer was not found guilty of a crime.”

Police only have to reasonably perceive a threat to justify shooting

The big reason Brailsford was acquitted: Police in America are generally given wide latitude to use force.

Legally, police officers’ most important line of defense in these shootings is whether they reasonably believed their lives were in immediate danger, not whether the shooting victim actually posed a threat.

In the 1980s, a pair of Supreme Court decisions — Tennessee v. Garner and Graham v. Connor — set up a framework for determining when deadly force by cops is reasonable.

Constitutionally, “police officers are allowed to shoot under two circumstances,” David Klinger, a University of Missouri St. Louis professor who studies use of force, previously told Dara Lind for Vox. The first circumstance is “to protect their life or the life of another innocent party” — what departments call the “defense-of-life” standard. The second circumstance is to prevent a suspect from escaping, but only if the officer has probable cause to think the suspect poses a dangerous threat to others.

The logic behind the second circumstance, Klinger said, comes from a Supreme Court decision called Tennessee v. Garner. That case involved a pair of police officers who shot a 15-year-old boy as he fled from a burglary. (He’d stolen $10 and a purse from a house.) The court ruled that cops couldn’t shoot every felon who tried to escape. But, as Klinger said, “they basically say that the job of a cop is to protect people from violence, and if you’ve got a violent person who’s fleeing, you can shoot them to stop their flight.”

The key to both of the legal standards — defense of life and fleeing a violent felony — is that it doesn’t matter whether there is an actual threat when force is used. Instead, what matters is the officer’s “objectively reasonable” belief that there is a threat.

That standard comes from the other Supreme Court case that guides use-of-force decisions: Graham v. Connor. This was a civil lawsuit brought by a man who’d survived his encounter with police officers, but who’d been treated roughly, had his face shoved into the hood of a car, and broken his foot — all while he was suffering a diabetic attack.

The court didn’t rule on whether the officers’ treatment of him had been justified, but it did say that the officers couldn’t justify their conduct just based on whether their intentions were good. They had to demonstrate that their actions were “objectively reasonable,” given the circumstances and compared to what other police officers might do.

What’s “objectively reasonable” changes as the circumstances change. “One can’t just say, ‘Because I could use deadly force 10 seconds ago, that means I can use deadly force again now,’” Walter Katz, a California attorney who specializes in oversight of law enforcement agencies, previously said.

In general, officers are given a lot of legal latitude to use force without fear of punishment. The intention behind these legal standards is to give police officers leeway to make split-second decisions to protect themselves and bystanders. And although critics argue that these legal standards give law enforcement a license to kill innocent or unarmed people, police officers say they are essential to their safety.

For some critics, the question isn’t what’s legally justified but rather what’s preventable. “We have to get beyond what is legal and start focusing on what is preventable. Most are preventable,” Ronald Davis, a former police chief who previously headed the Justice Department’s Office of Community Oriented Policing Services, told the Washington Post. Police “need to stop chasing down suspects, hopping fences, and landing on top of someone with a gun,” he added. “When they do that, they have no choice but to shoot."

Police are rarely prosecuted for shootings

Police are very rarely prosecuted for shootings — and not just because the law allows them wide latitude to use force on the job. Sometimes the investigations fall onto the same police department the officer is from, which creates major conflicts of interest. Other times the only available evidence comes from eyewitnesses, who may not be as trustworthy in the public eye as a police officer.

“There is a tendency to believe an officer over a civilian, in terms of credibility,” David Rudovsky, a civil rights lawyer who co-wrote Prosecuting Misconduct: Law and Litigation, previously told Amanda Taub for Vox. “And when an officer is on trial, reasonable doubt has a lot of bite. A prosecutor needs a very strong case before a jury will say that somebody who we generally trust to protect us has so seriously crossed the line as to be subject to a conviction.”

If police are charged, they’re very rarely convicted. The National Police Misconduct Reporting Project analyzed 3,238 criminal cases against police officers from April 2009 through December 2010. They found that only 33 percent were convicted, and only 36 percent of officers who were convicted ended up serving prison sentences. Both of those are about half the rate at which members of the public are convicted or incarcerated.

The statistics suggest that it would have been a truly rare situation if the officer who shot and killed Shaver was charged and convicted of a crime.

This is one reason body cameras were thought to be crucial: If people could just see more police uses of force, the thinking went, they could see how unjustified many of these incidents are. The Shaver shooting shows, however, that horrific footage may not always be enough.

American police use force more often than police in other developed countries

The scale of police shootings is, like many issues with gun violence, a uniquely American problem.

Police officers in the US shot and killed nearly 1,000 people in 2016, according to the Washington Post’s database — far more than other developed countries like the UK, Australia, Japan, and Germany, where police officers might go an entire year without killing more than a dozen people or even anyone at all.

For example, an analysis by the Guardian found that “US police kill more in days than other countries do in years.” Between 1992 and 2011, Australian police shot and killed 94 people. In 2015, US police shot and killed 97 people just in March. These differences are not explained by population, since the US is about 14 times as populous as Australia but, based on the Guardian’s count, has hundreds of times the fatal police shootings.

One explanation for this disparity is that violent crime is much more common in the US, putting police in more situations in which the use of force is necessary. As data from the Organisation for Economic Co-operation and Development shows, the US homicide rate throughout the 2000s was nearly four times the rate of Canada, more than four times that of the UK, nearly six times that of Australia, and more than 10 times that of Germany.

But why does the US have a much higher violent crime rate than other countries? One explanation: Americans are much more likely to own guns than their peers around the world. This means that conflicts — not just between police and civilians but between civilians — are more likely to escalate into deadly, violent encounters.

The research bears this out: More guns lead to more gun violence. Reviews of the evidence, compiled by the Harvard School of Public Health’s Injury Control Research Center, have consistently found that when controlling for variables such as socioeconomic factors and other crime, places with more guns have more gun deaths. One review of 130 studies in 10 countries, published in Epidemiologic Reviews, found that new legal restrictions on owning and purchasing guns tended to be followed by a drop in gun violence — a strong indicator that restricting access to guns can save lives.

For police in particular, one study found that every 10 percent increase in firearm ownership correlated with 10 additional officers killed at the state level over a 15-year period.

This is a result of cultural and policy decisions made by the US that have made firearms far more available in America than most of the world. For American police officers, this means they not only will encounter more guns, but they expect to encounter more guns, making them more likely to anticipate and perceive a threat and use deadly force as a result.

Other factors, such as differences in police training as well as socioeconomic and cultural variables, play a role in the higher rates of police violence as well. There are also sharp racial disparities in police use of force, with black Americans much more likely to be shot and killed by police than their white counterparts.

Whatever the cause, America simply has more police violence than comparable countries.

Correction: This article originally misidentified the officer giving orders in the video.