. . .
The CIA, usually portrayed as ruthless and omniscient, turns out to have had no spies and barely any informers in the enemy camp. Against al-Qaida, it was virtually blind and its leaders were paralysed by caution. When it did chance on two of the plotters and put them under surveillance in Malaysia in 2000, it almost immediately lost track of them.
The FBI, another supposed pillar of power, had sharp and dedicated agents around the country but their warnings were ignored by time-servers in Washington.
The bureau's computers were ancient and a barrier to the sharing of information.
The Norad military command, primed to defend against nuclear missiles, had not taken seriously the possibility that a commercial plane could be turned into a missile by hijackers.
The immigration service - so vigilant in barring some migrant workers from entry - failed to spot the hijackers' bogus passports, questionable cover stories and false statements on their visa application forms. Worst of all, the report presented a picture of a country failed by two administrations.
http://www.guardian.co.uk/september11/story/0,11209,1267542,00.html