"Likewise, don’t bother with the argument that if more people carried guns, they would deter shooters..."

“Likewise, don’t bother with the argument that if more people carried guns, they would deter shooters or interrupt them. Mass shooters typically kill themselves or are promptly caught, so it’s hard to see what deterrence would be added by having more people pack heat. There have been few if any cases in the United States in which an ordinary citizen with a gun stopped a mass shooting.”

- Do We Have the Courage to Stop This? - NYTimes.com