Apparently, the head of NSA said yesterday that if we were tapping phones without warrants before 9/11, "we would have detected some of the 9/11 al-Qaeda operatives in the United States."
This is what we in the business call "revisionist history." An NSA intercept lead the CIA to a meeting in Kuala Lumpur. The CIA identified several people at the meeting, and followed several of them with varying competence. They failed to ask the NSA to run the names of people through its database, which would have given better names, and running the names through the State Department would have revealed the fact that at least two people had visas to come to the US.
The CIA failed to pass on its information to the FBI, so when one of those men stayed with an FBI informant in LA, no one had thought to ask the informant to keep his eyes peeled.
According to NSA head Michael Hayden (who is now blaming the absence of warrantless spying for 9/11) "Throughout the summer of 2001, we had more than thirty warnings that something was imminent" (from Bamford's
A Pretext for War).
The hijackers stayed in a hotel just outside the NSA campus, used their real names, paid with a credit card, etc. They communicated with Afghanistan using internet chat at a local Kinko's.
Again, according to Bamford "For more than a year, the NSA had occasionally picked up [hijacker] Almihdhar's phone calls to teh al-Qaeda safe house in Yemen, never knowing that his calls were coming from the United States - or possibly even the same town."
On Sept. 10, the NSA intercepted two messages, one translates to "The match begins tomorrow," the other to "Tomorrow is zero hour." They came from al-Qaeda locations in Afghanistan, but were not translated until September 12.
And this brings us to a key fact about the NSA. Despite having the most powerful assemblage of computers in the world, there is vastly more material coming in than they can possibly analyze in a timely manner. It's difficult to imagine how increasing the workload would have made them more effective, given that the NSA, like the CIA and FBI, failed to capitalize on all the opportunities that al Qaeda gave them for years prior to 9/11.