Just a reminder, the time when Saddam was doing his main killing of Kurds, and involved in his main war of aggression, against Iran, was a time when his government was being given support and assistance by the USA. Including Donald Rumsfeld's notorious visit to Saddam.

Of course it was possible to use that as an argument for war, on the grounds "We created this monster, it's our responsibility to get rid of him", and I remember Clinton making a well-received speech to a Labour Party annual conference making that point.

But it's also worth remembering that that was not part of the actual reasons given for going to war by the White House, and that it would not have provided any legal justification for an invasion. (After all, how many other other "monsters" about which the same could be said are sitting in presidential palaces around the world?)