Then why is everyone so upset that the Deputie(s) didn't go into the school? If you were to see someone walking into a school with a gun, do you call people with guns or not?
The real fantasy is that we can make guns somehow disappear. When the police, from the FBI to the cop on the beat fail so completely, the potential victim is the last line of defense. In a situation where those who supposedly had the duty to protect, fail to do so, and it's down to the bad guy with a gun, what would you arm them with? A warm smile and a hearty handshake isn't going to work.
We cannot make guns disappear, but we can, in fact, make a lot of the guns disappear. Really. If we outlaw* guns, there won't be as many guns, and some of these spree killers will not be able to do it.
As for the ones who still manage, well, that's really a bummer and if the potential victims are not armed, it's true that they will have no way to defend themselves if we take away their guns. However, that's utterly irrelevant, for a few reasons.
1. Most of them don't have guns in the first place, and it's important to understand why not. They do not have guns. They do not have guns because they do not trust themselves with guns. They know that if you carry a gun, the most likely person to be harmed by that gun is yourself, followed by family, friends and close associates.
2. Most of them don't know how to use a gun effectively.
3. It doesn't matter if you know how to use a gun effectively if the "bad guy with a gun" has the element of surprise. It doesn't matter how good you are with a gun if he kills you before you can wield it. Similarly, if the good guy with the gun is not in the immediate vicinity when the shooting starts, the bad guy with the gun can kill a lot of people before the good guy(s) can stop him.
Note that these reasons overlap a lot.
Taking into account all of those reasons we conclude that although the outlawing of some guns, all guns, or some manner of gun employment (e.g. making it difficult to get a carry permit) will reduce the self defense capability of certain isolated individuals, it will make everyone, statistically, safer.
And that's what it all comes down to when it comes to gun control, at least when discussed by sane, rational, people. When viewed as statistics, people are less likely to die of gunshot wounds if we restrict guns. However, there may be certain rare instances where a given individual is less safe as a result of that restriction. The question is whether it makes sense to restrict an individual in order to achieve some measure of collective safety.
Unfortunately, very, very, few people are willing to have that discussion. Instead, the people who want very loose gun laws, like we have in the US, deny the statistical safety aspect. They refuse to look at the evidence staring them in the face that yes, gun control would make us safer, at least collectively.
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By *outlaw, I mean any significant restriction on the ability to acquire, sell, manufacture, employ, or own one or more types of guns.