I think everyone but the most partisan Republicans knows that had we never went into Iraq, continued with the policy of containment with Saddam, that today there would be no ISIS, there would be no civil war in Syria, there would be no strengthened Iran that was on its way to a possible nuclear bomb, there would be no Al Qaeda in Iraq, we would not have lost thousands of men there nor spent over a trillion dollars, and hundreds of thousands of Iraqi citizens would not have been killed.
Yes, Saddam was a bad man, but he was a contained bad man that was no longer a threat to us, our allies, or even for the most part his own people (due to no fly zones). The question was then would going in and toppling him leave Iraq better than it was before. We know the answer to that now and many of us figured we knew what would happen then. The fact that some on the war mongering right still doesn't get it is no surprise to anyone. What would you have us do? Keep tens of thousands of American soldiers there for decades to come, and spend a hundred million dollars a year or more for decades to come, just so we can hold the mess together?