ABSTRACT
Complementarity has been hailed as the 'cornerstone' and 'foundational principle' of the International Criminal Court (ICC) Statute. This chapter looks at what could be called 'vertical complementarity' and focuses on complementarity as a central feature of the ICC. It introduces the legalistic criteria for admissibility of cases and discusses whether the legal embodiment of the norm respects the spirit and objectives of the idea behind complementarity. It also presents complementarity as a broader idea that could spur the creation of a 'system' of international criminal justice that relies primarily on States. The chapter looks at what could be called 'horizontal complementarity' and focuses on States' obligations in the prosecution of international crimes that emanate from sources of international law other than the ICC Statute. It presents the relevant legal framework and current gaps in the international system and discusses some of their consequences in relation to States' contribution to the fight against impunity.
