The international laws of war have traditionally been divided strictly between those applicable to international armed conflicts, and those which are, in contrast, applicable to non-international, or internal, armed conflicts. On 22 March 1996, however, the President of the International Criminal Tribunal for the former Yugoslavia (ICTY), Antonio Cassese, sent a memorandum to the members of the Preparatory Committee for the Establishment of the International Criminal Court. The memorandum outlined the conclusions of the ICTY Appeals Chamber on this distinction, and asserted that:
since the 1930s, there has been a gradual blurring of the distinction between the customary international law rules governing international conflicts and those governing internal conflicts. Put another way, there has been a convergence of two bodies of international law with the result that internal strife is now governed to a large extent by the rules and principles which had traditionally only applied to international conflicts. … [R]egarding the formation of customary international law rules to protect those who are not taking part in the hostilities, … this convergence has come about due largely to the following four factors: (1) the increase in the number of civil conflicts; (2) the increase in the level of cruelty of internal conflicts; (3) the increasing interdependence of States; and, (4) the influence of universal human rights standards. The Appeals Chamber then turned to the extension of the rules regarding methods and means of warfare to internal armed conflicts and concluded that a similar blurring had occurred. In short, … certain norms apply as customary international law to internal and international armed conflicts alike.