Hey dave,..
they US already knew that Saddam and his sons werent nice people back in the 80's when they supplied him with weapons, (including anthrax), satellite reconnaisance and fully backed him in his (8year) war against Iran. (Im sure youve seen the nice clip of Rummy vigourously shaking hands with Saddam back when he was 'their bastard') Of course they also illegally supplied Iran with arms as well.

they didnt go to war to topple Saddam, because his sons fed people to the lions, but because of the threat of WMDs, remember Condi Rice Mushroom Cloud?, and an alleged link to Al Qaeda.
none of which materialized.