Willie could have prevented 9-11 by killing Osama. But, through the late 90s, he was taking Iraqi oil voucher money (and, maybe some Saudi money) to back off on pulling the trigger on OBL. Willie could have zapped him several times but didn't.
The dems, over the past 2 months, have been in full lie mode, screaming that there couldn't be a connection between 9-11 and Iraq and that anyone who said there was was an idiot. That was the first major clue. They only lie like that to protect Willie. Any investigation of the connection would lead back to Willie.
But, destruction of the paper trail is Willie's specialty. His sewer dwellers are experts at it. That's what Berger was doing, destroying evidence that Willie could have easily stopped 9-11 and that he was taking Iraqi oil voucher cash (through the same Mark Risch that he later pardoned).
Now, Berger and the faithful from Willie's White House sewer (Begala, Davis, Paneta, etc.) will deny it and belittle any who suggest it. They'll ask why would Berger or any one do such a thing. The answer is easy (the same answer as why Suzie went to prison for no reason), fear of Willie's long and deadly arm and the fact the Berger made millions dealing with the Chinese commies and, maybe, got a piece of the Iraqi oil money.