The Impact of Complementarity on National Implementation of Substantive International Criminal Law

Abstract

The complementary nature of the International Criminal Court (ICC) raises a number of pertinent issues with regard to the establishment of legislative frameworks for investigating and prosecuting genocide, crimes against humanity and war crimes on the national level. Such legislative frameworks reflect the aim of States to ensure that cases are not brought before the Court, because their laws satisfy the complementarity requirements. While complementarity thereby creates a strong incentive for national implementation, and arguably even involves an obligation for States parties, States have a variety of options at their disposal. As a rule, these options find their limits in the full criminalization of conduct that is also punishable before the ICC, although the Statute does not provide conclusive guidance with respect to a number of questions, including the availability of international immunities and the establishment of universal jurisdiction. The answers to these questions lie in a careful balance between minimalism and over‐assertiveness.