Another snippet from Without Precedent:
Before serving on the 9/11 Commission, Tom had not dealt with the world of classified Washington. When he got his security clearance, he took the train down from New Jersey for his first experience reviewing classified material. Phillip handed him a several-hundred-page FBI document with SECRET and TOP SECRET stamped all over it. He dove into it, as any curious citizen would.
When you review highly classified materials, there is almost always a security officer in the room – someone who stands by silently and watches you as you read. Tom carefully made his way through the classified FBI report, absorbing the secrets of the U.S. government. When he finished, he looked up at the security officer and said, “I knew all of this. There’s almost nothing in here that I couldn’t have known from reading the newspapers.”
The security officer looked at him and said, “Yeah. But you didn’t know it was true.”