We are on the horns of a dilemma, and it's a most uncomfortable place to be. I'm not opposed to guns and owned a rifle at one time. I do, however, see the Second Amendment differently than those loudest voices today. I think limits on ownership can be legally set, and so does the Supreme Court.
I also think if the Founding Fathers meant that amendment to apply to unlimited individual ownership (which I think they did not given the "well regulated militia" reference), then what they meant was that everyone had the right to own a musket. I have no problem with that. In fact, it solves all sorts of problems.
As a psychologist I naturally look for explanations of our self-destructive behavior, and in doing so, I considered some research from game theory dealing with "The Prisoner's Dilemma."
"You and your accomplice have been caught red-handed and placed in separate isolation cells. Both of you care much more about your personal freedom than about the welfare of your accomplice, but a clever prosecutor makes an offer. Together your best hope is to cooperate with each other by remaining silent. If so, you will each get off with a 6-month sentence. Either of you, however, can do better for yourself. Double-cross your partner, and you will go free while he serves 20 years. The problem is, if you each betray the other, you will both go to prison - and not just for 6 months, but for eight years. How should you each act?"
When you think about it, you recognize that no matter what your partner chooses, you should choose betrayal. Unfortunately, he is aware of that as well, and the inexorable tide of self-interest is going to carry you both up the river for eight years. Such is life.
In casual usage, the label "Prisoner's Dilemma" may also be applied to situations not strictly matching the criteria of the traditional game but where the players acting in their individual best interest create inefficient outcomes.
Consider patrons exiting a theater on fire. The surest method of saving the most patrons is for everyone to exit in an orderly manner. The surest method of saving yourself while everyone else is proceeding orderly is to rush the exit and get out first. If everyone rushes except you, you're toast. What typically happens is everyone, including you, rushes the exit, and many die - an inefficient outcome.
I think we can make a similar analysis of those whose reaction to the Tucson shootings is to bring their guns wherever they go. I have to admit the logic of having more guns brandished as a solution to the danger of there being guns present in the first place escapes me. Nevertheless, let's paraphrase.
Consider constituents attending an event. The surest method of keeping the most constituents safe is for everyone to leave their Glocks at home. If someone didn't though and started shooting, the surest method - perhaps - to save yourself while everyone else is dodging bullets is to brandish your weapon first. You shoot the shooter thereby saving yourself and reducing the number killed. Where we are headed, of course, is that everyone draws their weapons, and a mad gunfight ensues. Many die - an inefficient outcome. More guns is not the solution to gun violence.
By the way, don't think there are no risks for you if you are one of the few who are armed (the "good guy with a gun"). If I were the killer, I'm going to try to get you first when I see you're armed, then everyone else. And if you happen to kill an innocent in this firefight, you're guilty as charged - in spite of your good intentions. I hope you're a good shot.
It's insanity. Clearly.