As dawn broke on Sept. 11, 2001, America was asleep -- believing itself to be prosperous, safe and secure. Hours later, we gazed in horror and disbelief as the Twin Towers collapsed in a maelstrom of flame, smoke and debris. What did we learn? First and foremost, that there is evil -- real evil -- in the world. Evil regularly resurfaces in history. A generation ago, it took the form of the Soviet menace, and before that, of Hitler and his gas chambers. On Sept. 11, it crashed in on us in New York City, where it destroyed our complacent...