"Since Bill Clinton was Pres". Well since he didn't go after Bin Laden and Al Queda in the 90's in retaliation for the several attacks on his watch, you could say that he's to blame for all the attacks after his presidency, 9-11 and forward.
When he left office he gave the Bush administration all the warnings from intelligence in regards to Al Queda, yet he did nothing to seriously hamper their activity. He should have been the one to give the order to hunt down OBL even if he had to invade Afghanistan and take out the Taliban who was harboring and aiding OBL. That's the way I see it.