Jane Galt thinks the unthinkable

Maybe 9-11 wasn't a preventable "failure."

Maybe we should call this the Oswald Problem. It's hard to admit that a single twisted self-important punk can change history by killing a popular president. So we manufacture vast conspiracies at work in Dallas. Likewise, we want to believe that some one must have screwed up because 9-11 was such a great tragedy.

Maybe no one screwed up. Maybe 9-11 was just the result of a series of marginally flawed decisions which reinforced each other in a catastrophic fashion.

See also here.