Frank, sorry to nitpick with an otherwise excellent post, but while the letters of Osama bin Laden..states...the only reason to attack the US is because of American troops on "Holy soil" is true, but ...If we were to leave Iraq, Al-Qaeda could claim victory and not bother with America. isn't quite the case.
As far as Bin Laden is concerned, 'Holy Soil' means Saudi Arabia; that was the causus bellum on 9/11. That, too, is why the majority of the hijackers were Saudis.
However, Al-Queda presents in real terms a fairly minor threat to the US - and certainly a lesser one than the various far-right loony-tunes and fruitcakes in the militias and survivalist cults looking out for the black helicopters. Remember Oklahoma...