[andyfox]

It is my understanding that the approval from the special FISA court can be gotten after the fact. That is, that they can do what they want for 72 hours and get approval thereafter for what they did. And out of about 19,000 requests for approval, only five had been denied since the law was passed.

The law was passed with this in mind. Namely that the situations involving terrorism or other emergencies would require quick action that wouldn't necessarily come from regular courts.

If the Bush administration, in the aftermath of 9/11, had felt that FISA was inhibiting fighting the war on terrorism, they could have gone to Congress with a proposal to amend the law. Who in Congress would have opposed this?

The most obvious explanation for the failure to get approval from the FISA court is that is might not have been given. For the president to say that he didn't have to go to the court because of the Constitution or the congressional authorization for the use of force against Afghanistan is quite a stretch.