Of course it is also important that those who try to swarm a shooter go about it the right way. The approach needs to be as fast as possible, dodging from side to side like a football lineman to make one more difficult to hit, perhaps throwing things at the shooter along the way to distract him. It may also take more than two doing that.
It has been suggested that teachers should be armed, but that is not practical for such an unlikely threat. It is a mistake to prepare to depend on having a firearm that one will probably never need or not have when the time comes. A firearm can provide a false sense of security, and become a crutch. One must plan on doing without one, and if one has one available, use it as just another tool.
Metal detectors? One costs about $50,000. Armed guard? One would be about $40,000 a year. For 100,000 public schools, that would be about $5 billion and $4 billion/year, all for a risk that is so small that it is practically zero, despite anecdotal horrors. Even providing a firearm to every school would run $100 million. What are you going to cut out to pay for it? Stop all the sports programs? Cut out civics or history? Larger class sizes? What?
And neither of these things would have stopped Adam Lanza who just shot his way in, or any similar shooters would would do the same. Resistance to that would take rebuilding every school into a fortress, and that would make if difficult for kids to get in and out or do any outside events like sports. You might as well turn all schools into residential military schools operated like prisons.
A suicidal mass shooter is not going to be deterred by risk of being killed by an armed defender, only by risk of being stopped before he can kill enough to make his point. He can shoot his way in and do that in the first two minutes, long before someone with a firearm can get close enough to make the shot. The response has to come from the first few people he encounters.
It has also been suggested that the mother, Nancy Lanza, failed in her duty to prevent access to firearms by a mentally impaired family member, or that mental health institutions failed to provide support for treatment of Adam Lanza, but the reports so far indicate Nancy was doing what she could and that Adam showed no signs of being dangerous to himself or others. Without such signs it would not have been a rational decision to commit scarce resources to institutionalizing Adam when there are so many others who show more signs of being dangerous. Institutional care for the potentially dangerous mentally ill could easily double the entire cost of Medicare.
It is difficult for mentally healthy people to understand those who are unhealthy, but for our own safety it is worth trying. Some commentators have suggested that Adam was making a "cry for help", or was feeling "out of control" and trying to gain control, but those explanations are inadequate.
Contrary to popular misconception, most mentally deranged persons not only know they are, but are intensely dissatisfied and frustrated by not being able to do anything to become normal. That frustration can become violent rage against their situation and all the people in it, who are blamed for not being able or willing to help them. If they could they would strike at God, but they strike at whoever is near instead.
The reports also indicate Adam was intensely averse to frequent random human interaction. He was "anti-social" in the purest sense. How this can develop was brought out by John B. Calhoun's rat experiments, in which rats developed pathological behavior from what Calhoun attributed to excessive "density", but which is more precisely the result of excessively frequent stressful encounters. Since all encounters with others are stressful to at least some degree, a low tolerance for such stress would make being thrust into a crowd of humans, such as at a school, a living hell. The natural tendency for caregivers of such individuals is to cause them to have even more contact with even more others, hoping they will adjust. In most cases that might work, but in others it is the opposite of what is needed. Many people with such a problem retreat to a remote location and live out their lives as hermits. But some can avenge themselves for being the way they are by returning to the scene of where they first became aware of their problem and venting their rage on the sources of their pain.
There is always a risk in trying to assess the psychology of a troubled individual from news reports, but these explanations may be helpful for other cases even if they don't apply to Adam Lanza.
The solution is to train people how to defend without firearms, using only themselves and whatever objects might be at hand. People should not be trained to run or hide, but to attack with whatever they've got, and swarm the assailant. Their advantage is in numbers, and they need to use that advantage to take the shooter down. Yes, a few might get killed trying, but if enough try the loss of life is likely to be minimized.
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