In addition to having faulty intelligence, Bush had an "Iraq mission plan" that began before 9/11, and used 9/11 as a base of action and legitimacy. I don't think you could ignore the words of Gen. Zinnis and Clark who both said Bush was on a mission for Iraq, no matter what anyone said. Pressured intelligence and a yes-man cabinet led to Bush's decisions, not thoughtful analysis and a genuine risk assessment.
If you watched Tom Clancy's Fox News interview (which was only shown on TV once, I believe, what a surprise!), he said the Bush cabinet was proposing and bringing for review hysterical science fiction scenarios (unmanned anthrax bombers and floating barges of radioactive waste) of Iraq attacking us and he literally laughed in their faces. The signs and the dissent and the logic against the Iraq war were there, and they were considerable. Bush simply ignored logic and reason in a holy quest to go after Iraq.