There is a strong war crimes case against US and British leaders, but big powers have immunity
War crimes are always perpetrated by the loser in war. Though both sides may commit crimes, the victors have always been able to turn might into right, ignoring their own violations and penalising their enemy. At Nuremberg in 1945, the western states knew that their bombing of German cities could pose awkward questions and they quietly dropped their charges against the Luftwaffe; the democracies sat side-by-side with the Soviet Union, which many people argued at the time could itself be regarded as guilty on several of the same counts for which German leaders were indicted.
Should Saddam Hussein be caught alive, he will be made to account for years of crimes against humanity, if he is not murdered first by trigger-happy US forces. Western consciences will have no problems about arraigning Saddam and his henchmen. They will be expected to pay the way Hitler and his gang were expected to pay in 1945, though it is worth remembering that until a trial was finally agreed on in May 1945, Churchill preferred the idea that Nazi leaders should be shot on the spot once they were captured. Saddam might join Milosevic at the Hague, as a warning to tyrants worldwide that a grim justice awaits them.
But this time the situation is different. The legal position is anything but clear-cut. A good deal of informed opinion worldwide regards the Anglo-American invasion and conquest of Iraq as an illegal act of aggression, in the course of which it is coalition forces that have perpetrated numerous war crimes while pulverising Iraqi resistance. The Nuremberg precedent might be invoked to argue that committing crimes in order to overcome tyranny is legally permissible, but there is an awkward contrast with the treatment of German war crime in 1945: now it is the US and Britain that many believe have waged a war of aggression.
It is not difficult to imagine how the case for the prosecution against the coalition might be constructed. An indictment would have three main elements. In the first place, Britain and the US have waged an illegal war, without the sanction of a UN resolution (in itself of dubious legality when it comes to a war launched in violation of the UN charter and fought on this scale). Any argument that Saddam's failure to disarm fast enough justified the invasion of his state, the destruction of Iraq's major cities and the killing of thousands of Iraqis fails on the legal concept of proportionality. In British law, a householder may not cut an intruder to shreds with an axe on suspicion of burglary; if he does so, he becomes the object of prosecution. The suspected - but as yet unproven - violations of disarmament resolutions should not justify in international law the massive destruction and dislocation of the entire Iraqi state.
Ironically, the one instrument the Allies could find in 1945 to explain that Hitler's wars were illegal was the Kellogg-Briand pact, signed in Paris in 1928 at the behest of the then American secretary of state. The pact had outlawed war as an instrument of policy for all the signatory powers, including Britain and the US, but its precise status in international law was open to dispute. At Nuremberg, the American chief prosecutor, Justice Jackson, insisted on using it as the foundation for the whole case against Hitler. It could still be the foundation of the case against British and American belligerence.