> Scowcroft and Bush themselves said it was a goal of Gulf War I to leave
> Saddam in power
No, this is big nail but not quite on the head. The goal was, as Seth said, to have Saddamism without Saddam. This is a crucial point for understanding the immediate (if not the ultimate) motivation for this war.
If all they wanted was to leave Saddam in power, they could have concluded peace with Saddam and the war would have been a complete success.
But they decided it was essential to them that they couldn't negotiate with Saddam -- that that would count as a failure. So the US ended the war determined that Saddam would go -- but that the US would not personally do it because that violated the solemn promises made to the coalition. They felt fine about squaring the circle becuase they were positive that it would happen within a year. And When it didn't, they had no plan B.
And because this was their only acceptable goal, they -- and more importantly the right wing that constitutes their peers and audience -- considered GWI a failure rather than success, a complete failure, a moral and a strategic failure. And everyone involved was then chivvied for the next 10 years, that their sole memorable act on the historical stage was a pure and enormous failure.
The ad-hoc Plan B of sanctions and bombings which palliated this failure with a posture of realism and toughness was steadily unravelling. Without a war, it was becoming clear that it would eventually come to negotiating peace with Saddam. And the failure of this whole clan -- a failure constructed entirely out of their own self-understanding, their own weird morals, their own bad strategy, and their own belief in the magical 100% dependability of a deus ex machina coup -- would be set and be annealed in history's steel.
That was the underlying personal motivation of most of the decision makers involved -- to undo history and undo failure and make themselves from complete failures into complete heros in their own perverse terms.
Michael