That's what Mohammed Atta said.
If ANY of the cops that had stopped Atta driving around the U.S. on an expired visa had checked on that, 3000 more people would be alive today.
We don't need to turn into a surveillance state to maintain security.
In fact, we fought a Cold War against a foe with hydrogen bombs, enough chem/bioweapons to kill everything on Earth, and an active program of infiltrating spies and saboteurs into the U.S. WITHOUT requiring ID to fly.
Wear your chains lightly.
And just how would a national ID have pervented 9/11? All it will do is tag and track the movement of American citizens. The government knew who these people were, and even under today's laws, post 9/11, of not being able to single out for search more than 2 middle easteners, (heaven forbid we should annoy and inconvenience terrorists in an effort to protect ourselves) seems the only difference today is that it would be easier for these Islamic terrorists to carry out their evil plans.