"It's often been said, "Violence never solved anything." The simple truth is that when you are slammed up against the wall and the knife is at your throat, when a circle of teenagers is kicking you as you curl into a ball on the sidewalk, or when the man walks into your office building or school with a pair of guns and starts shooting, only violence, or the reasonable threat of violence, is going to save your life. In the extreme moment, only force can stop force."