While that seems to be the popular consensus... only history will be able to determine if Hussein, for example, might have turned out to be the Hitler of the Middle East. Neville Chamberlain made peace with Nazi Germany... Apeasement... a bad move in retrospect. I wonder what an early entry into what became WWII would have accomplished. Afterall, at that point the Luftwaffe was flying squadrons of biplanes painted on opposite sides with different squadron markings to make the apparent arms capabilities double... An early confrontation might have spared Europe that conflagration.
Who can say, without a doubt, that removing Hussein as the leader of Iraq hasn't averted a far more dire consequence.