Well Germany has the best single law probably in the world right now for prosecuting alleged war criminals. You can prosecute them anywhere in the world. They have universal jurisdiction. Ricardo Sanchez, who is the general in charge of all the of the military bases in Iraq, as well as the Iraq War during the Abu-Ghraib period, his Deputy Major Picowski and Colonel Pathos, they are all at U.S. military bases in Germany. They are people the German courts allege, along with Donald Rumsfeld, who were deeply involved in the abuses and torture that took place in Iraq. Germany is different from the United States in the sense that you can actually bring a criminal complaint and the prosecutor has to do something with it. He has to either investigate it, go ahead and do something, indict people, or he could reject it, but in any case you can always go to a court. The German complaint is 160-some pages, quite detailed. Most of it is based on the public record of what these people have authorized over a period of years. If people visit the CCR web site at ccr-ny.org, you will in a few minutes find a letter you can send directly to the German prosecutor urging the German prosecutor to begin a serious investigation.
A laudable thing to be doing, but the Americans will never let any of their soldiers, military or political leaders be tried in a foreign court and don't recognise the authority of international courts in upholding the standards of the Geneva conventions, etc. As a gesture it's very valuable though.
Indeed, they would undoubtedly never be imprisoned. The recent visit by Bush to Canada, was conducted under a cloud of domestic legal argument. What they have actually have done in Canada is say that because Bush is president, he can't actually be prosecuted right now in Canada until he's out of office, but that he should be barred from entering Canada because alleged war criminals, people who violate humanitarian law, cannot go into Canada and he should have been barred from entering Canada. This issue is not so much about violations of national or international law, but the conducting and asserting of the opposition to the war and it's methods.