A declassified report says we failed to sit in the Iraqi position to evaluate the evidence:
Analysts tended to focus on what was most important to us -- the hunt for WMD -- and less on what would be most important for a paranoid dictatorship to protect. Viewed through an Iraqi prism, their reputation, their security, their overall technological capabilities, and their status needed to be preserved. Deceptions were perpetrated and detected, but the reasons for those deceptions were misread.
One, Bush didn't lie us into war--he relied on CIA intelligence assessments that were wrong. Move on, OK?
Given that we had intercepts of Iraqi officers who sincerely believed that Iraq had chemical weapons, how would sitting in Iraqi shoes have helped? How would we prove that Iraqi efforts to foil inspections, move equipment around, and otherwise act like they had WMD were actually a deception in itself? Remember, Saddam was supposed to prove he got rid of everything as a condition in the 1991 ceasefire. It was not supposed to a trial where we had the burden of proof to show beyond a reasonable doubt that he still had WMD.
Saddam said he had them, we caught him building illegal ballistic missiles, he failed to account for all the chemical weapons raw materials, and Saddam kept the technicians and facilities to build chemical weapons.
I'd love to read an analysis of how our CIA would tell the president that Saddam acts like he has something to hide and has failed to account for all his capabilities to produce chemical weapons--yet since we can't prove he has them we conclude with high confidence that Saddam is bluffing.
Saddam bluffed and it isn't our fault he did so and believed our threat to destroy him was hollow.
Besides, if Saddam was bluffing, who believes Saddam would not have made good on that bluff the first chance he got? Which the way sanctions were crumbling in early 2001, would not have been long at all.
Saddam was a WMD threat and if we hadn't stopped him, he or his evil spawn would have had them--again.