An assault punishable in itself may be part of the graver offense of robbery, and it is proper pleading to charge both of the crime. So here the killing of defenseless civilians during a war may be a war crime, but the same killings are part of another crime, a graver one if you will, genocide - or a crime against humanity. This is the distinction we make in our pleading. It is real and most significant. To avoid at the outset any possible misconception, let us point out the differences between the two offenses.
War crimes are acts and omissions in violation of the laws and customs of war.
By their very nature they can affect only nationals of a belligerent and cannot be committed in time of peace. The crime against humanity is not so delimited. It is fundamentally different from the mere war crime in that it embraces systematic violations of fundamental human rights committed at any time against the nationals of any nation. They may occur during peace or in war. The animus or criminal intent is directed against the rights of all men, not merely the right of persons within a war zone.