Ok so just for something completley different heres something to think about;
The US government is on the verge of a complete economic failure, the national reserve has printed out more money than they can back in gold reserves, the Chinese economy is growing at an alarming rate, and Texan oil reserves are running out.
A certain government organisation comes up with a plan to implicate a former pawn used by the government to counter the USSR's plans to control Afghanistan, and uses his already increasing anti Western terrorist portfolio to implicate him in what can be called the next pearl harbour.
Altho the short term side effects include damage to the infrastructure and loss of life for US citizens, the long term effects offer the current government greater controll (Patriot Act) and nationwide support of a military movement into the middle east, and most notably oil reserves.
After the collapse of one of the most iconic american structers, and damage to the nations most protected installation the US invades iraq and we all know the rest.
Now this may be considered ridiculous, and its jsut a theory, but who can provide and concrete proof that something along the lines of this didnt happen.
JFK made a national address that talked about a major call for security coming in the near future, and said that it would be used for the wrong reasons by secretive societies within the government.
Finally, im not standing by this as an answer to anything, nor am i putting this forward as an explanation, i jsut want to raise the point that if this where in any means true, it would give more of a solid ground for some of the conspiracy theories to stand on. I feel that many of theories are instantly denied or treated as insanity purely due to the radical thinking that goes behind them, or because of how the differ so vastly from what people are willing to accept as normality.