Funny .. I think tha using the term "retarded" in any politcal discourse does no good for your cause.
Anyways .. I don't ascribe to the theory, but to say it wasn't bandied about as a reason for Bush the 2nd to go after Saddam and dismiss it out of hand is to not have been paying attention. It's based on two things:
First off at the end of Gulf I there were a LOT of people in the Bush Administration at the time who wanted to keep going and get Saddam. There were a lot of reasons not to - but the decision haunted many in the Administration. They won the war but Saddam was able to keep his regime. Sect'y of Defense at the time - Dick Cheney.
And then there's this statement by Bush: "There's no doubt he can't stand us. After all, this is a guy that tried to kill my dad at one time."
So .. there was a conventional wisdom that said that part of Bush's motivation was to "finish the job" in Iraq that his dad left undone.
Again - I happen to not ascribe to this particular line of reasoning, but it's not exactly the "nothing" you make it out ot be.
-P