IDs and the Illusion of Security

IDs and the Illusion of Security: "Our goal is to somehow identify the few bad guys scattered in the sea of good guys. In an ideal world, what we would want is some kind of ID that denotes intention. We'd want all terrorists to carry a card that says 'evildoer' and everyone else to carry a card that said 'honest person who won't try to hijack or blow up anything.' Then, security would be easy. We would just look at people's IDs and, if they were evildoers, we wouldn't let them on the airplane or into the building"