The underlying premise behind the notion of guns as an instrument of public safety, not just personal harm, is the “good guy with a gun” theory. The thinking goes bad guys will find a way to get access to a weapon one way or another no matter what laws are in place, because they are, by definition, bad. The most effective way to counteract a bad guy with a gun is for “good guys” to also have guns. That logic seems to square to some extent: Police having guns is not a particularly controversial idea. But beyond police officers, the gun rights advocates extend that logic to classify normal “good guy” citizens with guns as the most effective deterrent and most practical remedy to criminal violence, be it in a school or on the street. Bad guys are less likely to start trouble in a situation where they believe individuals are armed, and in case gun violence does break out, “good guys” with a gun are not only empowered to protect themselves, as armed good Samaritans they can act as first responders. This line of reasoning is so thoroughly ingrained in the rationale of the gun rights lobby that you need not look further than NRA chief Wayne LaPierre’s remarks at the CPAC conference Thursday to find an example of it.

"To stop a bad guy with a gun, it takes a good guy with a gun" Wayne LaPierre @NRA #CPAC2018 #CPAC #ATimeForAction pic.twitter.com/TGjJq3XNGT — CPAC 2020 (@CPAC) February 22, 2018

This argument—functionally promoting an arms race as a means of public safety—is not new to the NRA. It has enabled American gun laws designed on the assumption that if a bad guy might have access to a gun, so-called good guys must have a legal right to the same gun, big or small. This mutually assured destruction as deterrent, on a personal level, has wound its way from the NRA through Congress and into the Oval Office in the wake of the deadly school shooting in Parkland, Florida, last week.

Trump tells Florida shooting survivors that teachers should be given guns pic.twitter.com/d6qvJT11Sb — The Independent (@Independent) February 22, 2018

I never said “give teachers guns” like was stated on Fake News @CNN & @NBC. What I said was to look at the possibility of giving “concealed guns to gun adept teachers with military or special training experience - only the best. 20% of teachers, a lot, would now be able to — Donald J. Trump (@realDonaldTrump) February 22, 2018

....immediately fire back if a savage sicko came to a school with bad intentions. Highly trained teachers would also serve as a deterrent to the cowards that do this. Far more assets at much less cost than guards. A “gun free” school is a magnet for bad people. ATTACKS WOULD END! — Donald J. Trump (@realDonaldTrump) February 22, 2018

....History shows that a school shooting lasts, on average, 3 minutes. It takes police & first responders approximately 5 to 8 minutes to get to site of crime. Highly trained, gun adept, teachers/coaches would solve the problem instantly, before police arrive. GREAT DETERRENT! — Donald J. Trump (@realDonaldTrump) February 22, 2018

....If a potential “sicko shooter” knows that a school has a large number of very weapons talented teachers (and others) who will be instantly shooting, the sicko will NEVER attack that school. Cowards won’t go there...problem solved. Must be offensive, defense alone won’t work! — Donald J. Trump (@realDonaldTrump) February 22, 2018

The president’s solution is: More guns in America’s schools will mean less gun violence in those schools. A good guy with a gun would have saved lives at Marjory Stoneman Douglas High School when Nikolas Cruz went on a six-minute shooting spree before dropping his AR-15 rifle and walking out of the school building in an effort to blend in with students evacuating.

The problem is that there was a good guy with a gun at Marjory Stoneman Douglas High School that day. Security videos showed School Resource Deputy Scot Peterson was armed and in uniform on the school campus when the shooting started, Broward County Sheriff Scott Israel told reporters Thursday. But he stood by as the violence unfolded. “What I saw was a deputy arrive at the west side of Building 12, take up a position, and never went in,” Israel said. School Resource Officers are tasked with providing security on campus, and two other officers are facing an internal investigation for their response to the shooting. “They could have done more, they should have done more,” Israel said. When asked what the 54-year-old officer should have done, Israel responded: “Went in and addressed the killer. Killed the killer.”

Was Peterson not a “good guy” in the end? He was certainly not the right guy. We’ll surely find out more about Peterson soon, but his presence at the school during the shooting as a sanctioned “good guy with a gun” complicates the blissfully uncomplicated version of the “good guy with a gun” narrative on the right. It also shows the flaw in reflexively strapping holsters onto math teachers or volleyball coaches in America’s schools, in effect deputizing more “good guys.” How would 20 percent of America’s teachers, surely card-carrying good people by any definition, respond to similar pressures of the unthinkable? These questions of human frailty and error are nowhere to be found in the NRA’s “good guy with a gun” mythology, where the hypothetical armed hero is always batting a thousand, and for good reason. Once you allow for good people to be bad superheroes, to not save the day when everything was on the line, you start to look around for other solutions.