Since the political will to do this here may never exist, the U.S. should subsequently turn over George Walker Bush and Richard Cheney (if still living) to the ICC for war crimes (Iraq) and whatever basis Guantanamo can be prosecuted under (crimes against humanity? I am not a lawyer). Obviously, I am skipping a few intermediate steps.
I'd hope for the maximum penalties, after due process. I'm less concerned about also prosecuting subordinates, but there should probably be some cases there. My main concern is that the cases should start at the top and work down, rather than scapegoating a few underlings a la Abu Ghraib, at least domestically. Of course, preventing this sort of thing is exactly why the U.S. currently eschews the court.
I hold the vast majority of the U.S. military pretty much blameless, as in following their legally-given orders as best they can. Less so some of the "defense contractors" on the ground in Iraq, who seem to share the Bush-43 contempt for civilized norms. I am not looking to include Tony Blair's government, either, although some others in the world would do so. (Try googling "Abu Ghraib".)
My college roommate emigrated to Canada in disgust. I can understand the impulse, but that is not the answer. However, I don't see any way to clean house from here. If the current coverage of the so-called presidential contest is any indication, we'll never get there.
It would be much less stressful to stop following the doings of the world altogether. Frankly, if the Democrats self-destruct again, as seems increasingly likely, then it will be time to form a new political party. (Sorry, the implicit snub of the existing fringe parties is deliberate.) It's not that the Democrats walk on water, but the Republicans must take a hit for their (continuing!) support of the administration and its policies.
And now back to lurking under a rock...