When the whole becomes more than the sum of its parts: how the ICC re-invented itself through complementarity

Abstract

Complementarity is not only a technical-legal admissibility concept, but a structural principle of the International Criminal Court. In this contribution, I illustrate how dominant understandings of complementarity have shifted and evolved through practices and policies of the ICC and the Assembly of States Parties, without formal amendment or supplement of key legal instruments. I argue that complementarity has moved towards a new terra incognita and become more than the sum of its parts. It has taken on at least five different faces, through a mix of Court and governance practices: (i) complementarity as preservation of sovereignty, (ii) ‘positive complementarity’, (iii) complementarity as quasi primacy, based on the strict interpretation of the same person, same conduct’ test, (iv) ‘positive complementarity 2.0’, adopted as a follow up of the Independent Expert review, and (v) ‘regional complementarity’ which re-defines the ICC’s relationship to other international institutions, including regional justice mechanism. These faces emerged gradually in the course of the ICC’s institutional history, but continue to co-exist simultaneously. This diversification extended the meaning of complementarity beyond its original statist conceptions.