This week, The Ringer is taking time to travel all the way back to … last year. Or a few months ago. We’re diving into the not-so-distant past to check up on what happened to that one lady, or to track the rise of an online social movement. Welcome to Recent History Week, where we’ll explore events you may have forgotten about and remind you why they still matter.

Last July, the Dallas Police Department used an explosive during a confrontation with a sniper named Micah Johnson, who had assassinated five police officers during a protest against police brutality. Cornered in a parking garage stairwell, Johnson promised to kill again. After a two-hour standoff, the police decided further negotiations were futile, and sent an 800-pound Northrop Grumman robot with a bomb attached to its body toward Johnson. They detonated the explosive remotely. He died on the scene.

"Other options would have exposed our officers to grave danger," Dallas Police Chief David Brown explained at a press conference the next day. The improvised robot bombing had been unorthodox, but it had minimized the risk of yet another officer dying. Pursuing a radical course to keep officers safe was a thoughtful choice, made under considerable duress. Brown’s emotional and tactical logic was manifest — but it also had troubling implications. Delivering a lethal explosive with an unmanned device is now a proven option for American law enforcement, but one notably lacking in guidelines or limitations, even more than a year after the precedent was set.

Since Dallas, there has not been another incident in which a U.S. police department has deployed an unmanned device to kill a suspect, but that does not mean it was an anomaly. Peter W. Singer, a strategist at the D.C. think tank New America who has written a book about technology and warfare, told me that he suspects the Dallas bombing will mark the beginning of a trend. He is concerned that there is an absence of oversight, and he wants federal guidelines to be implemented before robot bombings become commonplace. "Do you want each and every police department figuring this out on their own?" he said. "You want it to be something that the [Department of Justice], Congress, the police academy and training organizations, the courts, and the public all weigh in on, rather than taking an ad hoc approach."

There is no centralized national police force in the United States. Instead, the country is patrolled by a variety of state and local law enforcement agencies, with help from federal entities with law enforcement arms. The Department of Justice, for example, contains the Federal Bureau of Investigation and the Drug Enforcement Agency, among others. This mosaic of law enforcement departments is united by a common objective: to keep Americans safe by enforcing the law. This is distinct from the military’s objective, which includes fighting and destroying international adversaries. The United States does not have a gendarmerie like France or Spain, where a paramilitary doubles as the police. America’s civilian police force is supposed to protect and serve exclusively. Waging war is not in the job description.

Don’t tell that to Dave Grossman, though. Grossman is one of the most popular police trainers in the United States. One of his seminars is shown in the 2016 film Do Not Resist, a jarring documentary following various local law enforcement departments as they adopt military equipment, tactics, and attitudes. "Violence is your tool," Grossman tells seminar attendees in the film, advocating for the police to fight violence with "superior violence." Grossman openly advocates for the increased militarization of civilian law enforcement. It appears he is getting his way.

Many police departments around the U.S. already own to the type of robot that was used in Dallas. In 2015, a Northrop Grumman spokesperson told Vice that 90 percent of police bomb squads use the company’s robots. A Pentagon program called 1033 allows civilian law enforcement to obtain unwanted military devices, including its surplus robots. This program is also responsible for arming U.S. law enforcement agencies as if they were extensions of the armed forces. From 2006 to April 23, 2014, according to an NPR investigation, the Pentagon’s 1033 program provided police with 205 grenade launchers, 79,288 assault rifles, and 11,959 bayonets, in addition to more than 600 mine-resistant ambush-protected vehicles, which are essentially a cross between an armor-plated Hummer and a tank. In addition to 1033, the Department of Homeland Security began providing grants for purchasing military equipment after 9/11. "Police agencies have a whole new source of funding for their war gear," the journalist Radley Balko wrote in his 2013 book, Rise of the Warrior Cop, noting that small-town forces were frequently the recipients of these powerful weapons, and that they tended to use them in increasingly ordinary situations, particularly run-of-the-mill search warrant executions for narcotics. "Just as they’d done with the 1033 program, they’d argue that the equipment was necessary ‘just in case’ of the school shooting or Al Qaeda attack in Fon du Lac. But once they get the gear, they use it for drug raids."

Bard University’s Center for the Study of the Drone has tracked instances in which civilian law enforcement has acquired robots from the military. By 2016, according to the center, about 700 robots had migrated from the Pentagon to the police. The center suspended its tracking research last year, but codirector Arthur Holland Michel told me that, barring a significant change of policy, he believes that the number of unmanned devices transferred from the DOD to police has if anything sharply risen. "I’m certain that the numbers have increased dramatically over the last year, simply on the basis of how the numbers were tracking," he said. "There are more law enforcement in the U.S. operating these systems than there were last year."

Most of the robots used by police are deployed for nonviolent tasks; one was even used to deliver pizza to deescalate a negotiation with a suicidal man. Just last month, the Flagstaff, Arizona, police force used a robot similar to the one deployed in Dallas to end a standoff with an armed suspect, although in that instance they simply sent the robot to open the suspect’s door before entering. Often, the robots are used to defuse bombs, not carry them.

Some police departments have already begun planning to use other types of unmanned devices as weaponry. In North Dakota, for example, state legislation permits the police to operate armed drones, as long as the weapons aren’t lethal, which means they can be equipped with tear gas, pepper spray, rubber bullets, and TASERs. (The Connecticut General Assembly considered a similar bill this year, but it failed in committee.) In Albuquerque, New Mexico, a police bomb squad used a robot to deploy chemical munitions to force out "a barricaded subject armed with a gun" in 2014. As law enforcement continues to stockpile and grow stashes of military-grade robots and weaponized drones, the opportunities to use these tools are bound to increase.

Unmanned weapons are commonplace in the military. Singer described an Iraq War situation that mirrored the events in Dallas. "In this case, the soldiers took duct tape and a claymore mine, and basically duct-taped the mine to the little robot. They drove it down the alleyway, and blew the [enemy] soldier up, rather than send their soldiers down the alleyway, so it’s a similar kind of example of an ad hoc solution using a robot," he said.

Bombs are also commonplace in the military, but still rare in civilian law enforcement. As Singer pointed out, while the bomb deployed in Dallas did not end up harming anyone but its intended target, the most notable example of a police force using a bomb on civilians had a far different outcome. In 1985, a police helicopter dropped a bomb on a rowhouse on West Philadelphia’s Osage Avenue, killing 11 people, including five children. The resulting fire spread far past its target, engulfing and destroying 61 houses. The bombing was a calamity. "It’s like Vietnam," a local resident named Steve Harmon told The New York Times that year. The police claimed they had wanted to destroy the compound that members of the radical group MOVE had built on top of their building, but after the explosion did not knock it down, the fire consumed a large swath of the neighborhood and burned up most of the people inside the house (the majority of whom were women and children). The documentary Let the Fire Burn, which relies on archival footage to tell the story of this ignominy, portrays the enormous collateral damage, with sweeping shots of the destruction.

Deploying a remote explosive is an act of escalation, not deescalation, and while sending in a robot protects a human from harm, it also keeps the human at a remove from the situation. Pulling a trigger while looking into a suspect’s eyes, reading their body language, and hearing their words is different from detonating a bomb while at a distance. "Removing police from danger is a completely understandable imperative, but by lowering the risk of killing suspects, an increase in use of unmanned explosive devices could result in an increase of lethal apprehensions," Singer said.

Technology ethicist Patrick Lin, who has briefed the CIA on the risks of deploying weaponized robots, is also concerned that while lethal robots decrease jeopardy for police officers, it means they may become a too-frequent fallback. "It’s a psychological and economic truth that when costs go down — such as risk of injury to yourself from a certain activity — then demand or engagement in that activity goes up, everything else being equal. Robots can save police lives, and that’s a good thing, but we also need to be careful it doesn’t make a police force more violent. That’s a tricky balance to strike," Lin told me in an email.

In the case of the Dallas Police Department (which did not respond to requests for comment for this story), the explosive robot was deployed as a last resort. In the future, however, there is good reason to worry that the threshold will be less clearly defined. Should police use a robot bomb only when an armed suspect has repeatedly proved that they plan to kill police? Or can law enforcement blow up any suspect engaged in an antagonistic, armed standoff? Without guidelines, these decisions are left to a patchwork of police forces that have access to powerful technology without much by way of policy limiting their use.

"Next time that a police department tries to replicate what police in Dallas did, it may go horribly wrong," Michel said.

And while the robot used by the Dallas Police was maneuvered into place by a human officer, technology for more autonomous lethal devices already exists. Mary Wareham, the advocacy director for the arms division of Human Rights Watch, sees the Dallas robot bombing as an incident that highlights how quickly technology is progressing. "We call for a preemptive ban — which means we are concerned with future weapons systems, rather than the existing ones. But in order to kind of understand what’s coming, it helps if we can ground the discussions in the types of weapon systems that we see today, because there are many different kinds of weapon systems with increasing autonomy, or the other way to look at it is with decreasing levels of human control," she said.

American law enforcement has widespread access to military equipment, including weapons, but are not trained with the rigor of the military. The weapons they are accumulating have been designed for warfare, not for peacekeeping, which makes it all the more necessary to create regulations about how to convert tools of combat into tools of community safety, as well as rules for when war machines are simply inappropriate and dangerous to wield. In Dallas, the decision to use the robot likely saved lives, but it is not safe to assume that every police department with this capability will behave with as much prudence, as police brutality continues to plague the United States. The reason that the Dallas police officers were patrolling to begin with was because people were gathering to protest the fact that unarmed black people, including Philando Castile (whose killer, Officer Jeronimo Yanez, attended a seminar called "Bulletproof Warrior"), had recently been killed by law enforcement. Police departments in the U.S. have struggled and failed to apply appropriate use of force as their weapons stockpiles have increased. It is important to prioritize their training and corresponding policy-making to ensure that civilian law enforcement’s booming repertoire of robotic and automated weaponry is used judiciously. A national discussion is in order for how to narrow the circumstances in which a robot with a bomb is even floated as a possibility — and where the robots, explosives, and other weapons transferred from the military to the police belong in rotation on the streets. Right now, law enforcement has an interesting opportunity to follow policies that stress community-building and guardianship over treating people like threats; establishing reasonable limits for when unmanned explosives are permitted would send a heartening message.

"Our own people are not the enemy," Lin said.