Justin S. Yang, PhD Researcher at King’s College London; LL.M at Leiden University.] The International Criminal Court (ICC) projects a legal framework that is unique from the prior expressions of international criminal justice. In the construction of its Statute, in particular through the system of complementarity, the Court embodies the potential to actualise a horizontal and communitarian system of justice; rather than mandating a singular perspective of law in a vertical hierarchy, the ICC framework is designed to accommodate the inherent plurality of its international membership. Tracing the development of international criminal justice institutions in the 20th century has illustrated that this project has been in oscillation between peak periods of heightened inter-state cooperation and trough periods of resistance to encroachments on Westphalian sovereignty. The respective institutions that were established following World War I, World War II, and the Cold War have predominantly reflected the interests of only the particularly powerful states, albeit under international communitarian rhetoric. Prior to the ICC, exercises in international criminal justice were exclusively facilitated first by the key multinational states of the post-war Allies, and later by the P5 of the UN Security Council. Rather than devising a new justice system that could be compatible with sovereign equality and the multiplicity of legitimate legal systems on the international plane, the post-war multinational bloc opted to adopt the vertical trial-based nature of Western domestic criminal systems. In other words, these judicial institutions, acting on behalf of the multinational leadership, presided at the apex of their respective scope of adjudication, in the same way a sovereign reigns supreme in its domestic system. Mirroring the capacities of the sovereign, these international judiciaries were unchallengeable, and arbitrarily made claims to various laws, as understood and accepted by them, onto diverse heterogeneous situations. In this penetrative hierarchy, sovereign boundaries and the indigenous legal systems of the subject state were explicitly disregarded and disapplied by the adjudicators. Therefore, diverse circumstances, local peculiarities, and contextual relevancies, all of which could materially affect the process of adjudication and determination of culpability, failed to be considered. The crimes were analysed solely through the perspectives of the multinational victors. The ICC marks a departure from this tradition of vertical justice. The democratic legitimacy inherent in its treaty-based creation, and its central tenets of independence and impartiality has, in theory, separated criminal adjudication from overarching political agendas, including that of the UN Security Council. The symbiotic relationship between the Court and its member states, within the complementarity regime, has allowed for a horizontal, stateless, and impartial system of justice to exist over the global community. Being complementary to national systems means that the Court preliminarily defers to a state’s sovereign prerogatives to exercise criminal jurisdiction over international crimes. This prerogative is perceived as a duty of every state (Rome Statute, Preamble). Upon failing this duty at a standard deemed acceptable by the Court, the case may then be admitted into the ICC docket. State proceedings are therefore inherently underpinned by the implicit threat of the Court ‘seizing’ the case, if the framework of preventing impunity (Rome Statute, Article 17) is not satisfactorily upheld.