Darnella Frazier recorded more than 10 minutes of George Floyd’s killing. The video, shot with her cellphone, captured an audience in addition to the violence. One woman, who identified herself as an off-duty firefighter, pleaded, then demanded, that Minneapolis Police Officer Derek Chauvin and his colleagues check Floyd’s pulse. A man berated the officers, calling them “bums.” A teenage cashier, who had originally summoned the police, rushed outside, panicked, before a pair of onlookers walked him back inside. By minute six, a crowd had gathered. Officer Tao Thou stood between them and Floyd’s body, which was still pinned under Chauvin’s knee, and lurched at anyone who stepped off the sidewalk.

Later, after Frazier posted the video to Facebook and the country convulsed in protest, a debate ensued: The other officers had abided the killing happening in front of them, but hadn’t the bystanders, too? Couldn’t someone have rushed the cop? Forced Chauvin to lift his knee, just for a moment?

On CNN, a lawyer for one of the officers shifted blame from his client by suggesting as much: “If the public is there and they’re so in an uproar about this — they didn’t intercede either.” An Orlando Sentinel op-ed argued the same: “Have the courage to intervene against racist aggression,” its title read. Comments posted to Facebook underneath Frazier’s video dressed their criticisms less delicately: “I would’ve pushed his dumb ass off,” one commenter wrote. “I sure wouldn’t of stood there and watch any man die for no reason,” wrote another. The backlash was so loud that Frazier felt compelled to address it. “I am a minor ! 17 years old, of course I’m not about to fight off a cop I’m SCARED,” she responded on Facebook. “Fighting would’ve got someone else killed or in the same position [as] George.”

Floyd was killed with a knee, not a gun, but criminologists and community activists interviewed for this story agree that Chauvin’s sidearm nonetheless enabled the violence. Guns attend virtually all instances of police brutality, allowing officers to exercise force with little fear of resistance from victims or intervention from bystanders. Law enforcement agencies understand this; in early June, to help de-escalate tension at protests in Washington D.C., the Pentagon ordered responding National Guardsmen not to carry firearms or ammunition. “We’re here, but we’re walking things down,” an anonymous defense official told The Washington Post.

“Guns are the extreme logical end of what the whole training and whole repertoire of policing is about,” said Rutgers sociologist Frank Edwards, who studies the relationship between civilians and law enforcement, referring to police officers’ force-oriented approach to problem solving. “I can’t imagine police acting the way they do without a firearm.”

Edwards and other sociologists stressed that a wide body of research casts doubt on bystanders’ willingness to intervene during times of crisis. Studies have shown, for example, that people are less likely to react to signs of fire when in groups than when alone. Tracey Meares, an expert on policing and law at Yale University, said she suspected that this tendency to watch, rather than engage — known as the “bystander effect” — would extend to instances of police brutality, as well.

But almost no research into the bystander effect specifically focuses on instances in which police kill or brutalize Black Americans, the videos of which have become their own gruesome genre. In these videos, bystanders frequently make some attempt to intervene, shouting at police and in some cases physically assaulting them. So it was during Floyd’s killing. As CBS reporter Wesley Lowery noted in a tweet about the video, several bystanders to Floyd’s arrest were “desperately attempting to intervene” throughout, just not physically. Frazier explained her hesitance to get physical as a fear of being shot — a reasonable one considering that police kill Black Americans at twice the rate of white Americans, despite Black people accounting for less than 13 percent of the U.S. population. But even if this is not a full diagnosis, it points to a very real power deficit that few social scientists have studied: American police always have guns. What, realistically, could a bystander do?

Jason Coupet had his driver’s license for less than two months before his first run-in with the police. The Black 16-year-old lived in south suburban Chicago at the time, and had an aunt who lived about six miles away. He said that one day, leaving her house, a police cruiser pulled onto the road behind him. For 20 minutes, it followed him down winding streets, turn after turn, without lights or siren, all the way to his home. When he pulled into his driveway, lights flashed. “I got out of my car, because that’s what you do when you park in your driveway,” he said. The two officers in the cruiser — both of them white — got out of theirs. “They unholstered their weapons,” he remembered, “like a sheriff about to do a draw, and they just started cussing. ‘Get the fuck back in the car’ — that sort of stuff.”

Coupet’s mother rushed outside when she saw what was going on, yelling at the officers to let her son be. He says they abruptly holstered their guns and changed their tones. “They told her I didn’t signal coming into my driveway,” he said.

Coupet, now a professor of public administration at North Carolina State in Raleigh, posted about this experience and several others in a Twitter thread following Floyd’s death. He told me that, in his experience, police have goaded him to escalate, not the other way around — cursing at him, following him for miles, always waiting for a mistake. He said officers often feel empowered to behave this way because they have guns. “It changes what they think they can get away with.”

Police have always understood that firearms facilitate abuses of their power against Black people. As early as before the Civil War, “Slave Codes” — and later “Black Codes” — prohibited Black Americans from owning guns, enshrining this advantage in law. In the late 1960s, after racist ownership restrictions had fallen away, the Black Panthers tried to close the power differential, assembling shotgun-armed posses in Oakland, California, to observe officers as they interacted with Black civilians. They met the implicit threat of a police shooting with the equal threat of an armed intervention, and officers relented: With the Panthers present, traffic stops and arrests occurred without beatings.

“The Panthers understood that guns changed the dynamic, that an officer was going to be less likely to harass them if the officer thought that they could exercise self defense,” said Adam Winkler, a professor of constitutional law at the University of California, Los Angeles, and the author of Gunfight: The Battle Over the Right to Bear Arms in America. “That’s why they carried the guns.”

The Panthers’ tactic didn’t last — state legislatures and Congress quickly passed laws restricting access to guns and the ability to carry them openly in public. In fact, many political historians believe that American lawmakers would never have found a cause in gun control without a parade of armed Black people on magazine covers and news shows stirring anxiety in the white populace.

Winkler said he sees an echo of the Panthers’ logic in the growing chorus of activists calling to defund the police as protests over Floyd’s killing continue. “The defund-the-police idea, I think, is in many ways about de-arming the police and de-militarizing the police,” he said, adding that the strategy recognizes that guns almost always undergird police violence.

Many countries choose not to arm the bulk of their police forces. Iceland, Ireland, New Zealand, Norway, and the United Kingdom all deploy police officers on regular patrols unarmed, with most reserving firearms for specially trained officers who respond to situations involving armed suspects. The United States is unique in that nearly all police officers carry a service weapon, and are instructed to use it to kill if they use it at all. The distinction has deadly consequences. According to an analysis conducted by the Prison Policy Initiative, a nonprofit research firm that studies criminal justice, U.S. police kill civilians at more than 16 times the rate of police in countries where law enforcement officers work unarmed. Edwards, the Rutgers sociologist, said this owes to a “ceiling effect” when a gun is present. “The ceiling of how bad something can go is death when there’s a firearm involved — that’s really the difference.”

The obvious caveat to any international comparison is America’s rate of firearm ownership. Americans own 46 percent of the global total of civilian-held firearms, according to a 2018 report from Small Arms Survey. That’s almost 400 million guns — or more than one gun per person, or 50 times the number owned in the United Kingdom and 3,700 times the number in Iceland.

“You can’t understand the landscape of modern American policing without considering the widespread availability of firearms here,” said Michael Sierra-Arévalo, a sociologist and criminologist at the University of Texas at Austin, who has written extensively about policing in the United States. He said fears of armed encounters pervade American police culture. Officers “are socialized to understand their work as one interaction, one moment away from death,” he said. “Everybody is a threat.” Black people bear the brunt of that mindset, despite reporting lower rates of gun ownership than whites. Law enforcement agencies routinely over-police predominantly Black neighborhoods: During the heyday of New York City’s stop-and-frisk policy, for example, police stopped Black people six times as often as their white counterparts, even though whites were more likely to be found with a gun.

Sierra-Arévalo recalled an interaction that revealed the extent of police hypervigilance. During some field work, he asked an officer about the well-documented tendency of police to touch the rear of cars they stop for traffic infractions. “That’s to make sure the trunk is closed so that a gunman doesn’t jump out and kill me,” the officer answered. Sierra-Arévalo was skeptical. After some back and forth, the officer admitted it was an extremely unlikely event — it had never happened to him, nor had he heard about it happening to anybody else. “But that’s how we’re trained,” he insisted. “We expect to find somebody with a gun, somebody who’s trying to hurt us.”

This locks America in a Catch-22: When activists call for an end to police brutality, they inevitably point to the gun. In order to dismiss the possibility of meaningful reform, police do the same. Each group is acknowledging the reality that, in conflicts, guns heighten stakes. For many Black Americans, though, these charged encounters have come to define their relationship to the police. As Yale sociologist Monica Bell phrased it to me, to many Black and Latinx people in America, “the police and the gun are synonymous.”

Bell, who studied the turbulent police-community relations that made a tinderbox of Ferguson, Missouri, leading up to the police shooting of Michael Brown in 2014, told me that it’s not necessarily that people in heavily policed communities consciously fear being shot in every police interaction. Instead, most know — because of this association between officer and gun — that police possess an absolute authority to use force in all its varieties.

For decades, activists have alluded to this reality when describing the police. “A cop is a cop,” James Baldwin told the poet Nikki Giovanni in 1971, during a conversation on PBS. “He may be a very nice man, but I haven’t got the time to figure that out. All I know is he’s got a uniform and a gun.” Nearly 50 years later, on the streets of Minneapolis, activists relate to police the same way. “We don’t want people with guns coming into our communities,” one protester told Minneapolis Mayor Jacob Frey, in a viral Twitter moment that ended with demonstrators chanting “shame” as Frey skulked out of the crowd. The protester was referring to the police.

Bell has coined the term “legal estrangement” to describe the sense of exclusion pervasive in over-policed communities. Community members, she explains, feel that the police show up not to protect them, but to protect the outside world from them. In her research in the aftermath of the Ferguson uprising, Bell concluded it was legal estrangement that had set the stage for the eruption of grief and rage that consumed the city and the country in 2014. She said exactly the same tensions boiled over when George Floyd was killed.

Javier Lopez, a violence interrupter who works for the Red Hook Initiative Youth Development Center in Brooklyn, agreed. He told me that people have to understand “how unnatural and not normal it is, that from cradle to grave people walk out of their buildings and are met with police, who have guns on their hips.” What message does it send to young Black and Latinx children, he asked. “It’s a war response, but in a war there’s two sides.” It raises the implicit question: Who are the police at war with?

Since George Floyd’s death, Lopez has been hopeful about the possibility for an overhaul of the country’s approach to policing. He has watched the country’s young people normalize a radical vision of public safety, one that might, for the most part, remove firearms from the picture. He pointed to the Minneapolis City Council’s intention to dismantle the Police Department, and the phone tree system they proposed to dispatch social workers to respond to some 911 calls instead of armed police. He said he thought that violence interrupters would make good candidates for this kind of first responder. Unlike the police, he said, “the brothers and sisters doing violence interruption work have an aversion to holding a firearm.”

He continued: “That’s because it’s not war for us. It’s peacekeeping.”