Last week it happened again. Another school. Another disturbed young person. Another needless firearm legally purchased. Another good person dead as a result. Last Tuesday, a 28 year-old former Spanish teacher named Shane Schumerth walked into the office of Dale Regan, the principal of the school where he had been recently fired, pulled out an AK-47 assault rifle and killed her before committing suicide. A week earlier, T.J. Lane, a 17 year-old Ohio boy, took out his .22 semi-automatic pistol and killed three people and injured two more. And the week before that, a third-grader grabs the family's legally bought...