Atrios asked a question several days ago, and Bush apologists still can’t answer it:

No one has yet managed to explain how revealing that the administration illegally spies on American citizens without obtaining warrants, instead of legally spying on people after obtaining such warrants, damages national security.

The only plausible answer is that the revelation clues in suspected terrorists that their communications are being monitored.

But don’t they already know that??  Isn’t that why they talk in code?