Whether it was the massive short selling of airline and insurance stock just prior to 9/11 that apparently went unnoticed, or the comings and goings, suspicious contacts and training among many known associates of Muslim terrorist groups that were never investigated, there was a massive failure.
With all the technology and safeguards in place, who was manning the ship?
Americans; Americans sleeping at the wheel.
Actually, I truly believe that some in positions of authority are guilty of CRIMINAL negligence. Worse than that, it wouldn't even surprise me to someday find out that someone accepted a bribe to look the other way. They should be swinging at the end of a rope, but I am afraid it will never happen.