A remarkable revolution has taken place in the field of internal armed conflicts in the last fifteen years. Coming out of decades of torpor, the law regulating internal armed conflicts has evolved dramatically on a number of levels. As seen in chapter 1, the definition of internal armed conflicts has been developed and consolidated by international judicial institutions such as the International Criminal Tribunal for the former Yugoslavia (ICTY) and by state practice through the negotiations of the International Criminal Court (ICC) statute. Even if the precise determination of a state of internal armed conflict remains a difficult and controversial exercise, a consolidated definition of internal armed conflict has taken shape. Common Article 3 and customary law principles regulate internal armed conflicts defined as ‘prolonged armed violence between governmental forces and organised armed groups or between such groups’ within a state. Protocol II and its higher threshold of applicability has lost importance, as most of Protocol II provisions are reflected in customary law and apply in this generic category of internal armed conflicts. This definition, however, does not settle all difficulties, since states can still claim that the violence in their countries does not reach that threshold. States enjoy a broad discretion in the regulation of internal disturbances and sporadic armed violence which fall below the established threshold.

Secondly, there has been the clear development of a solid body of customary law regulating internal armed conflicts.