Lots of people on both ends of the political spectrum supported it at the time, because Baathism truly was nightmarish, and because almost everyone disastrously

Lots of people on both ends of the political spectrum supported it at the time, because Baathism truly was nightmarish, and because almost everyone disastrously overestimated the competence of American war leadership. But, whatever the rationale amongst the rest of the "Coalition of the Willing" might have been, the core claim of the war's instigators in the US was WMD. Regime change was a mechanism for decisively eliminating terrorist threats.