For the horrible details, you can read about here or here or here.
So how will this go over? There are those on the left who will see this as an indictment of the war, and further reason to leave. They will be met by either a deafening silence or various rationalizations by those on the right who support the war and don't care to talk about any of their military heroes being murderers and rapists.
Here's my opinion. This particular war had nothing to do with what this guy and his cohorts did, except it gave them the circumstances in which they thought they could get away with something like this, like all wars do. The vast majority of soldiers are decent guys doing their jobs, but all armies have their share of criminals and psychos and ours is no exception. And whatever I normally feel about the death penalty, this guy should be put to death and anyone who helped him, or even helped him try to cover up what he did, should die in prison.
So there you go.