Giving The People What They Want.
A recent poll found that 36% of the Americans questioned believed that the US government "either assisted in the 9/11 attacks or took no action to stop the attacks because they wanted the United States to go to war in the Middle East."
If these morons have such a hard-on for a conspiracy theory about 9/11, I'll give 'em one: Nearly all of America's smart people were killed in the 9/11 attacks. For evidence of this, I point to the aforementioned poll as well as two others. The first found that nearly 70% of Americans found it "at least likely" that Saddam Hussein was involved in the 9/11 attacks, despite overwhelmingly conclusive evidence to the contrary; the second uncovered that 30% of Americans could not remember in what year the 9/11 attacks took place.
This new conspiracy theory of mine would also explain why we haven't been attacked again. Having killed off most America's smart people, al Qaeda figures that we can finish the job of destroying our country on our own.