well...
Ouch, but what would the immediate driving force behind the attacks be? Would Iran blow up civilians by accident in Afghanistan and then refuse to acknowledge that it happened? Because that's what the US did to piss off Bin Laden AFAIK. If the Iranians did something that made Al Qaeda attack them, then yeah. Would the US fund them? Maybe. Until Tim Osman(Bin Ladens code name that the CIA knew him by during the Soviet war in Afghanistan) does something to the US itself that actually catches the public's attention and outrage, I think they would continue to look the other way. After all, Osama had very rich family members who dealt in business all over the world. I think that would help him fund it plenty, but hey, a few billion dollars more is all the better

. Though 'fun' fact... While 9/11 was happening, Vice President Dick Cheney was meeting with one of Bin Laden's brothers to secure a business deal...
Side Note: This post was meant in a serious fashion even if it seemed like I was a little not being serious, which I do to keep the mood from sinking too low. I apologize if it caused offense to anyone, that was not my intention if it does.