I'm swayed by
Yglesias. Even if Saddam did have nuclear weapons, the best thing to solve that crisis was to have the UN inspectors continue with their work. Especially when the intelligence we did have was so shaky. The UN inspectors were finding out that there was no active weapons program during the winter and spring of 2003. This was taken as a sign that inspections were not working, because they did not fit the expectations of the hawks in the administration.
The Nigerian documents we received from the Italians that Bush based his Jan. 2003 State of the Union claims on were considered to be highly dubiuous by the State Dept., the CIA and the FBI at that time. If that is not an example of ignoring evidence that does not fit your desired outcome, I don't know what is.
I'm afraid that in all the shouting about who knew what and how and by twisting which arms, we are forgetting a crucial lesson from all of this: preemptive war is a losing strategy.