Where is the opposition to the war coming from?

I disagree with the author that this is the reason, but it is "a" reason:

Forget all the articles about incompetence, failed plans to "win the peace" and all the rest of it. Americans don't care about that and never will; nor do they care about Iraqi schools or share the President's obsession with some foreign people's craving for "democracy". What they cared about was the war they were sold on, i.e. that the United States was taking the gloves off and from this point forward would wage war against international terrorist organizations and the governments that sponsor them.

Had Bush waged that war, the support would have held. Given how badly Bush has strayed from the "Bush" Doctrine, I'm frankly surprised that the support for him didn't wane earlier. In fact, given the "Islam means peace, the Saudis are our friends, and we must respect women of cover" rhetoric coming out of the White House, tied to the fact that our military obviously is fighting with one hand behind its back, it's *amazing* Bush's support held out as long as it did.