Here's an interesting case to examine: former Marine with handgun stops a crime.
It's a fine example of the sort that gets trotted out by our NRA friends to say, "See, it works! And all you crazy liberals want to take away our protection!"
And yes, of course, sometimes is does work. Have yet to see an argument to the contrary. A lot has to go right, and thank heavens it did here. Kudos to Mr. Blackmore. It probably helped that he had intense training in the military; most of us don't.
It's also a fine example of something that would remain completely unaffected by tightening restrictions on high-capacity magazines and on certain rifles. (He had a handgun.) Please read that twice if you're tempted to embrace the "take all our guns away" canard.
Worth noting, too, that a gun is often entirely unnecessary to stopping a crime. The details notwithstanding, this is something I know from experience. Might have been better or worse if a gun had been involved.
How many situations like this happen every day, to all kinds of people? How many variations play out? Some perpetrators have guns; some interveners have them; some victims have them. The complexities and sudden turns of such situations mean, I contend, that sometimes a gun is an advantage, and sometimes it means innocent people get shot.
Carrying a gun is a very big responsibility, and raises the stakes in such situations enormously. It's worth considering, no matter what side of the current debate you fall on, what outcomes are possible.