I’m a pragmatic pacifist who wishes to minimize violence and I accept that some violence might be necessary to accomplish this. Of course, everyone says that they want to minimize violence, so how is a pacifist like me any different? The difference is one of Bayesian probabilities. I believe that the probability that violence will reduce other violence is very small in wartime. I accept just war theory in theory, but in practice it just never seems to work out, so I look at history and judge that the chance of the violence of war to be the best way to minimize violence is very, very small. In contrast, police officers have a long history of using violence (and mostly just the threat of violence) to reduce worse violence and that has mostly worked well, so I’m fine with policing even though I would hate to have to personally carry a gun and threaten people with lethal force. I’m a bit of a hypocrite because I’m not willing to do the work of a police officer myself, but I’m glad that other people do it and I’m happy to summons a police officer if I think that they could reduce violence via their ability to threaten violence (deterrence).
This idea is basically the same as just war theory. Just war theorists argue that although the violence of war is bad, a just end can justify the means. I accept that premise in theory, but in practice, I see very little probability that it has ever worked to minimize violence and death. As Helmuth von Moltke the Elder said, “No battle plan survives contact with the enemy.” Just war theory fails in practice because as soon as the fog of war descends, the plans for both the means and the ends change unpredictably. On the other hand, the logic of just war theory really does to work to support the use of violent means (and mostly just the threat of violence) in policing and criminal justice. This has had a very high probability to achieve ends that are more just and less violent than the alternative (anarchy). There are certainly exceptions to this rule, but I’d argue that it applies for all societies with at least moderately dense populations and governments that are more than minimally competent. In other words, it works in the places where the vast majority of humans live today.
So I’m happy to support the idea that a bad guy with a gun are usually stopped by good guys with guns (the police). But there is a category of bad guys with guns that cannot be deterred by good guys with guns. Rob Reid explains:
But killers bent on suicide are notoriously tough to deter. Some deny this — like the fantasists who burble about armed guards preventing school shootings. But in schools and elsewhere, mass shootings happen under the noses of armed guards all the time.
This includes the canonical spree at Columbine. That school indeed had a well-trained, armed defender on duty. But he in no way mitigated the massacre’s outcome. A common retort is that if one gun’s not enough, then lots of campus guns should surely do the trick! But what’s the effective dose? Four armed guards? Forty armed teachers? Four hundred armed students?
How about 45,000 trained soldiers? That’s the resident population of Fort Hood, the largest U.S. military base. And it couldn’t stop a wimpy shrink from killing 13 and injuring dozens in 2009 (although he didn’t die during the attack, the perpetrator intended to, so he classifies as a suicidal mass murderer.) Five years later, a second gunman at the base killed four and injured 13 before killing himself. Fort Hood could presumably fend off an ambitious military onslaught. But a lethal defense is no deterrent to an attacker with a death wish. Indeed, it’s a massive added attraction.
The Fort Hood mass shootings prove that arming and training lots of good guys with guns doesn’t stop bad guys with guns from committing mass shootings.
One of the problems is that you don’t know ahead of time who will become a bad guy and giving lots of people guns and training them to kill also means creating a worse bad guy problem because it makes more people more lethal if and when they switch over to the dark side. It is hard to know who is going to become a bad guy in advance, and it is harder to predict who will become a mass murderer when there are more and more people to keep track of because more and more people have weapons of mass destruction like machine guns.
The other problem is the element of surprise and planning. Even if lots of good guys have guns like at Fort Hood, the bad guy is going to be well aware of that fact and plan accordingly for positioning himself in a easy-to-defend sniper position. Even those mass shooters who didn’t care about planning basic defensive tactics have usually been able to rapid-fire kill a bunch of people before getting shot down just due to the sheer advantage of surprise.
So unless the bad guy shoots himself first, good guys with guns always stop bad guys with guns… eventually, but the best way to stop bad guys with guns from killing people is to keep bad guys from getting weapons of mass destruction in the first place.
(Note to pro-gun fanatics: You won. Sensible gun control is politically impossible in the US, but I don’t care much because other issues are much more important for public health anyhow.)