As a category of international crimes, crimes against humanity are universally prohibited by the customary rules of international humanitarian law. Unlike other international crimes, namely, war crimes and the crime of genocide, the concept of crimes against humanity had no conventional base in international humanitarian law until the adoption of the ICC Statute, which is the only international treaty setting up the conditions and the substantive content of crimes against humanity in detail. 1
As will be indicated in this chapter, the notion of crimes against humanity was one of the most important outcomes of the Second World War. This is because the concept and the individual criminal responsibility in this regard were, for the first time, introduced and enforced by the International Military Tribunals at Nuremberg and Tokyo. 2 Since the Second World War, the concept of crimes against humanity has evolved and become an independent category of international crimes. In this sense, the most significant developments are the adoption of the Statutes of the ad hoc tribunals (the ICTY and the ICTR) and of the ICC those of which give power to these international criminal institutions to try and punish individuals responsible for crimes against humanity. 3
In international humanitarian law, today, it is well-established that the norms governing crimes against humanity have reached the level of jus cogens and States' duty to prosecute, punish or extradite the individuals responsible for crimes against humanity is an obligatio erga omnes in nature. 4 Despite the nature of the rules on crimes against humanity, there
1. Art. 7 of the ICC Statute (known as the Rome Statute of the International Criminal Court which was adopted by the United Nations Diplomatic Conference of Plenipotentiaries on the Establishment of an International Criminal Court on 17 July 1998, UN Doc. A/CONF. 183/9, 17 July 1998 and entered into force in accordance with its Article 126 on 1 July 2002).
2. See infra, p. 241, The Concept of Crimes Against Humanity.
3. Art. 5 of the ICTY Statute; Art. 3 of the ICTR Statute; Art. 7 of the ICC Statute.
4. See supra Chapter 3, p. 78, Crimes Against Humanity. And also see Final Report of the Commission of Experts Established Pursuant to Security Council Resolution 780 (1992) (hereinafter Final Report), para. 73. The latest practice of the international community in terms of confirming that the norms of international humanitarian law prohibiting crimes against humanity enjoy the status of peremptory norms of international humanitarian law or of jus