9/11 was OBL's response to Clinton's failed missile attack on his terrorist camp, which was in retaliation for the African embassy bombings.
Bush, IMHO, had been doing very well in Afghanistan: use of CIA and special forces, combined with cooperation from locals, on a clearly defined search-and-destroy mission. OBL was almost caught.
Then, all of this success was thrown away to conduct an open-ended occupation campaign against Iraq. Certainly, US forces could quickly defeat the Iraqi military, but most experts, even Republicans, agree that there was insufficient planning for dealing with the administration of Iraq post-invasion.
What of the power vacuum created by Saddam's removal? What of the regional stability which Saddam provided against Iran? Unfortunately, it seems the Bush administration failed to consider this.
Instead, Bush has led the U.S. into the same booby trap as Vietnam. A war of occupation with no defined goals, no end in sight. A war for which the US military is not trained to fight. Like quicksand, it pulls you in deeper the harder you fight against it.
IMHO, I see no more point in fighting this war. All I can suggest is that the US turn Iraq over to the UN to split into 3 distinct countries, and hope that Iran doesn't take advantage of this.