The media rarely mention the mass murders that were thwarted by armed citizens at the Shoney's Restaurant in Anniston, Ala. (1991), the high school in Pearl, Miss. (1997), the middle-school dance in Edinboro, Penn. (1998), and the New Life Church in Colorado Springs, Colo. (2007), among others.

WSJ: David Kopel: Guns, Mental Illness and Newtown