Governments get over such spates of moral indignation very quickly. The minute another Yugoslavia happens, and Europe wants U.S. troops so that they won't have to send in their own, Iraq War #2 will be forgotten.
A theory posed by a friend of mine: we Americans should pull our troops out of Europe, but Europe wants our troops there so that they can spend their tax dollars on social programs instead of domestic defense. I have no opinion on whether that's actually what's going on, but I find it an interesting idea.