Revisiting the Customary International Law Avenue: Immunity of State Officials of Non-Party States in the Enforcement Proceedings of the International Criminal Court

The International Criminal Court usually must rely on the States Parties to the Rome Statute to arrest and surrender suspects. Since the Court can assume jurisdiction over Non-State Parties' officials, a dilemma thus arises of their immunity when this occurs as it did in the recent arrest warrant for Putin. This article primarily examines one of the avenues explored by the Court to remove immunity, specifically the Customary International Law Avenue. First, under this Avenue, the Court removes "vertical immunity" by arguing that either (1) international courts gradually constitute exceptions to traditional customary immunity rules, or (2) traditional customary immunity rules are never applicable in international courts. However, this article contends that both approaches are difficult to justify. The former fails as relevant evidence does not meet the threshold of constituting exceptions to existing customary rules. The latter is similarly untenable as it does not provide a convincing definition of what is known as "international courts" which could legitimately justify the different application of immunity rules in these and in domestic courts. Second, this Avenue proceeds to remove "horizontal immunity" by recharacterizing States Parties as surrogates of international criminal jurisdiction rather than exercising domestic criminal jurisdiction which renders "horizontal immunity" irrelevant. This article argues instead that there is a difference between States Parties assuming an international obligations and implementing them domestically. Additionally, the Rome Statute grants considerable deference to States Parties for arrest and surrender within their own territory which makes it inappropriate to regard these as mere "jurisdictional surrogates" of international criminal jurisdiction. If the Customary International Law Avenue is ultimately adopted, it would have a profound impact on the practice of the International Criminal Court and beyond.