Something the 9/11 Comission "missed"

Oops, U.S. knew of al Qaeda cell before 9/11.
I guess this all pivots on the definition of the verb "know" and whether or not you can say that the US "knew" something or if it was just a group of 10 people who work for a super secret group that "knew" something. Nothing hammers home a mistake like some hindsight, but you'd really think that the 9/11 comission would have picked up on this one. Oh well... at least Bush and the neocons got their "new Pearl Harbor", right? Remember what those crazy assholes over at Project For a New American Century said? No? Read page 63, column 1, sentence 1 of this pdf where it reads "Further, the process of transformation, even if it brings revolutionary change, is likely to be a long one, absent some catastrophic and catalyzing event – like a new Pearl Harbor."
At least they called it "catosrophic".