Here's a good link I saw today on CNN of all places.
Ted Nugent (don't laugh) does a pretty good job of explaining what the problem is and what an effective solution would be. He also gives some poorly publicized examples where his solution (the same one I proposed yesterday) has worked effectively. It seems that criminals usually turn out to be cowards when armed citizens confront them and if they suddenly decide to be brave then their criminal careers reach a premature conclusion. I'm hard pressed to see how that is bad.