Grave offenses against the laws of warfare entailing the penal responsibility of individuals constitute war crimes, long punished according to national laws and procedures. At the international level, war crimes were first clearly defined after World War II by the Charter of the International Military Tribunal. The international experience with prosecuting and punishing war criminals was followed by the codification of rules in the 1949 Geneva Conventions, the 1977 Additional Protocols, the statutes of international criminal tribunals for former Yugoslavia and Rwanda, and most recently, in the Statute of the International Criminal Court.

Much earlier precedents for punishing war crimes can be found in ancient Greece and Rome, the Laws of Manu in India, the code of Bushido in Japan, the Old Testament and the Qur'an. Violations of the laws and customs of war were punished by military commanders or national tribunals....