Why did they do the wiretaps illegally?

I'm seem to be losing track of the distinction between what I said in conversation and what I've written here. I feel like that character in the movie Le Weekend who kept asking at various points in the movie: is this real life or is this a movie?

In the context of the NSA's illegal wiretaps, why not get the FISA court's approval? Ah-ha! I remember, I did blog this here. Short answer: because they knew it was wrong.

Atrios has the same thoughts:

Now we know the program involved illegally spying on large numbers of innocent people with no connections to terrorism.

Through all of this the question really has been -- why? None of the claims by Bush defenders have held up at all. The only reason I can come up with that makes any sense is that if you institute a program which illegally spies on large numbers of innocent people it's much easier to hide the real targets of the operation.