George Friedman (Stratfor) presented the idea in 2005ish that the WMD lie, while a lie, was done for valid reasons (essentially as an excuse to send troops to destabilize governments that might later have provided legitimacy/money/sanctuary to al Qaeda; and further to warn other governments in the area that to shelter al Qaeda would be a very bad idea). Obvious problems with that aside (the irony of Pakistan, for example), I think it's the kindest excuse anyone has ever offered for the invasion of Iraq. I wonder if anyone (Hillary, Dick Army, whoever) saw through the lies but accepted the side-premise that an invasion might nonetheless help for other reasons, and then after the fact when it was a catastrophe just pretended they bought the lies to save face.
There isn't a person in the world who was paying close attention who didn't know they were lying. The real question marks were to what extent they were lying and what their actual policy objectives were. The answers seemed obvious to most of us liberal minded folks at the time: A LOT and OIL. Turns out we were right, which was sad given that their policy objective failed so miserably that the reason for us being there became obscured in favor of something like "providing security for Iraq," a self-made problem. The real irony here is that Al Qaeda wasn't there until we invited them in.