A deep look into the legal meaning and practical implications of the complementary principle of the Rome Statute

Abstract

The groundbreaking creation of an International Criminal Court (ICC or the Court) in the political arena was accompanied by the establishment of an innovative principle in the legal field: the principle of complementarity. This principle governs the relationship between the Court and the States parties to its constitutive Treaty, the Rome Statute. It postulates that national courts investigate the commission of genocide, crimes against humanity and war crimes (international crimes) and prosecute their perpetrators, unless they are considered incapable to do so. In last resort, the Court intervenes and prosecutes the offenders. So, national courts are given priority to adjudicate international crimes, under the condition that they fulfil certain requirements. Complementarity therefore involves complex legal definitions and procedures to set up this conditional priority system. The Court being five years old, the legal meaning of complementarity may be confronted to its practical implications in order to comprehensively grasp the real effects of the concept. The key question therefore concerns whether the practical impact of complementarity confirms or invalidates its legal meaning. Finally, issues resulting from an application of complementarity may be identified from this wide understanding of the concept. If the legal definition and the practical impact of complementarity presuppose a particular role for the Court, solving these issues might call for a rethinking of this role. Adjusting the missions of the Court to respond to these particular issues intends to maximise the positive aspects of the practical implications of complementarity while remaining within its legal definition.