There is one commentator whose words should enlighten us on the meaning of Saturday's shooting of Rep. Gabrielle Giffords and the savage murders that took the lives of, among others, a federal judge and a 9-year-old girl. The person is Giffords herself. In an interview last March, the Arizona Democrat anticipated almost everything being said now and explained why what happened on Saturday is a violation of our national self-image as "a beacon." Our pride, she said, is that "we effect change at...