Larison suspects that we were hoodwinked:

Supporters of the Libyan war are annoyed whenever anyone makes comparisons with Iraq, but there is one thing that the two wars definitely have in common: both of them initially relied very heavily on how the respective dictators wanted their enemies and the rest of the world to perceive them. Both wars are the product of taking dictatorial bombast and saber-rattling as if they are reliable indicators of future behavior. Despite having no WMDs, Hussein wanted to cultivate the suspicion and fear that he did have them to exaggerate his government’s power. It is conceivable that Gaddafi was engaged in a similar bluff. As in Iraq, outside governments may have reacted to an empty threat.

Related thoughts here.