That's one of the central reasons a regime change op in Saudi Arabia would have been more justified. I think the rational explanation is that Team Bush wanted

That's one of the central reasons a regime change op in Saudi Arabia would have been more justified. I think the rational explanation is that Team Bush wanted war, but couldn't directly attack Iraq (the efforts to link Al Qaeda and the anthrax letters to Saddam were largely unsuccessful), so they went into Afghanistan instead. The complete abandonment of 'nation-building' Afghanistan in 2002 as all efforts shifted to invading Iraq sort of supports this scenario.