There's another way to phrase that and that is that the absence of evidence is not the evidence of absence. It is basically saying the same thing in a different way. Simply because you do not have evidence that something does exist does not mean that you have evidence that it doesn't exist.

The reality is that terrorists can attack any time at any minute, 24 hours a day, using a variety of techniques, in any place at all. And it's not possible to defend in every place, against every technique, against every conceivable approach. It means that you can't stop every terrorist attack. Innocent men, women and children are going to be killed if terrorists are determined to do it.

One of your tasks is to separate the 'personal' from the 'substantive.' The two can become confused, especially if someone rubs the President wrong.

If I know the answer I'll tell you the answer, and if I don't I'll just respond cleverly.

No terror state poses a greater or more immediate threat to the security of our people and the stability of the world than the regime of Saddam Hussein in Iraq.

Don't say 'the White House wants.' Buildings can't want.

The price of being close to the President is delivering bad news. You fail him if you don't tell him the truth. Others won't do it.