In a working-class neighborhood in a midsize Northeastern town, a police officer is driving his cruiser down a darkened street when he passes a group of six Latino teenagers walking and talking together. “Look at these little shitheads,” he mutters. He stops his car, throws it in reverse, and backs down the one-way street, unholstering his pistol and laying it in his lap. When he reaches the group, all of whom are boys, he rolls down his window and, keeping the pistol in his lap, just out of sight, points it at them through the panel of the cruiser door. “What’s up, guys?” the officer says. “What’s up?” they reply. He questions them about how they’re doing in school; they joke nervously about their grades. Eventually, without acknowledging their jokes, the officer ends the encounter. “All right, you guys stay out of trouble,” he says and then drives away, slowly reholstering his pistol.

In the passenger seat, Michael Sierra-Arévalo, a sociologist at the University of Texas at Austin, silently observes the interaction. Soon enough, the officer explains the unholstered gun: “They would have been able to shoot at us in a split second if they wanted,” he says. “You have to be ready for that. Always have a plan of attack.”

This short but haunting exchange illustrates a central ethos of American law enforcement, as Sierra-Arévalo argues in a new book, The Danger Imperative: Violence, Death, and the Soul of Policing. In quietly reaching for his firearm, the officer was indulging a now-routine impulse. It may be irrational, given how rarely police are attacked. But policing, as a profession, is obsessed with violence and officer safety, a worldview that Sierra-Arévalo calls “the danger imperative.” Within its ambit, the officer’s actions make perfect sense.

A focus on danger pervades police culture, from drills in the academy to self-defense tactics on the street. Officers are taught from the start that the very people they are sworn to serve might harm them at any moment: Even if department policy states that they are never to draw a weapon unless an emergency arises, the philosophy of policing in America is to treat every interaction as a potential crisis. And despite the modern color-blind logic of the profession, police disproportionately use these tactics in poor communities of color, often causing harm.

“The danger imperative is policing’s governing institutional frame,” Sierra-Arévalo writes. More simply, it is “the ‘soul’ of policing.” The Danger Imperative studies several police departments around the country to catalog the often hidden mechanisms that animate police violence. Beyond that, Sierra-Arévalo reveals how danger has become a useful focus for a reactionary social project: A vigilant police force is a necessary ingredient in protecting the interests of both capital and the state. In an era when demands for racial and economic justice have reached a fever pitch, the book explains how a preoccupation with violence helps perpetuate a system of inequality.

It was Michael Brown’s death in Ferguson, Missouri, and the rise of the Black Lives Matter movement that convinced Sierra-Arévalo that he should study cops. People filled the streets, decrying long-standing patterns of police brutality; the police responded with tear gas, nightsticks, and arrests. To some pundits, policymakers, and police representatives, these confrontations amounted to a “war on cops,” the latest rhetorical front in a counterrevolutionary battle, growing since the 1960s, that targeted protesters as criminal enemies. When disturbed citizens ambushed and killed police officers in New York City and Dallas, it only served as further proof that the thin blue line between chaos and order was under attack. Never acknowledged by this same commentariat is that policing today is safer than ever. It’s not danger-free, of course: Officers suffer a violent injury rate more than 16 times the national average for all jobs. But deaths in the line of duty have dropped by 75 percent in the last 50 years, and violence against police has not spiked since 2014.

Why, then, do police see threats all around them? To understand this phenomenon, Sierra-Arévalo spent four years, from 2014 to 2018, observing three police departments in the Northeast, the Southwest, and the West, pseudonymized as Elmont, Sunshine, and West River. From the moment that officers join the force, he found, they are bombarded with the message that the public is out to get them. In academy rooms bedecked with military imagery, instructors screen grisly videos of officers murdered on the job. “Reality-based” scenarios suggest, falsely, that hidden guns are common during traffic stops. A PRISim simulation video in Sunshine teaches recruits when to “neutralize” an armed suspect—and how to justify it despite the department’s stated policies. This tough-sounding “tactical” stuff far outweighs the instruction on defusing potentially violent situations. Elmont, for example, devotes 170 hours to weapons training and just 10 to de-escalation techniques. The ruling message of police education, Sierra-Arévalo writes, is that their work is defined by “a constant fight for survival that must be won at all costs.”

On the job, a barrage of information reiterates the lethal dangers of policing. Public memorials to fallen officers are ubiquitous. Elmont’s headquarters displays plaques for each officer killed on duty going back to the 19th century. Privately, officers possess a “hidden world of cultural artifacts” to commemorate the dead: bracelets, tattoos, and personal shrines. Meanwhile, the daily functions of the department reinforce the sense of threat. Sierra-Arévalo takes us into the “lineup” room where officers start their shift; there the walls are plastered with warnings about volatile gang members and exotic weapons. Supervisors distribute “hot sheets” with information about violent crimes around the region. Never mind that these offenses represent a tiny fraction of any agency’s thousands of routine calls for service; they take center stage in the police imagination. Occasionally, actual violence strikes. When an unruly crowd in West River injures an officer during an illegal street race, her colleagues understand the incident as confirmation of the widespread danger to police across the country in the wake of BLM. “This just goes to show how the climate is right now,” one tells Sierra-Arévalo. “It’s disturbing how violent and aggressive people are with officers.”