Modalities of the exercise of universal jurisdiction in international law

It has become a trend today that states adopt universal jurisdiction in their domestic law. At the same time, the actual exercise of universal jurisdiction has often led to a dispute among states. While there are many ‘international’ aspects relating to this phenomenon, there is still no consensus among international scholars even over the scope of crimes that are subject to universal jurisdiction, let alone the modalities of its exercise. This confusion is caused by the way in which jurisdiction is conceptualized: while prevailing view sees jurisdiction as a right or entitlement attributed by international law, this view is premised on a particular understanding of the legal system of jurisdiction that sees it as a set of permissive rules of international law. However, it may not capture the reality of jurisdiction, where international law does not always regulate the assertion of prescriptive jurisdiction, while the actual exercise of jurisdiction is still subject to several restraint either in relation to other states or with regard to the rights of accused individuals. Against this background, Part I of the dissertation re-examines the legal system of jurisdiction and applies it to the specific framework of universal jurisdiction. First, this study seeks to find the elements that actually restraint the exercise of jurisdiction in general. It concludes that the exercise of jurisdiction should be examined from the perspective of whether and to what extent it may secure effectiveness of enforcement, legitimacy (necessity) of claim, and foreseeability of law and forum. Building on this analysis, this study further seeks for a justifying ground of universal jurisdiction by applying the general framework of jurisdiction. It is suggested that at least the legitimacy (necessity) of claim is provided by the fact that states have been less interested in tolerating impunity for certain types of international crimes and also been more aware of the necessity for the exercise of jurisdiction in order to compensate for the failure of territorial or national states of the offender in the suppression of these crimes With those insights, Part II further explores a framework in which the conflict resulting from the concurrent claims of jurisdiction. The focus is on the idea of subsidiarity, which designates universal jurisdiction as a default mechanism. While this idea has been gaining support, it is pointed out that the feasibility of subsidiarity depends on how situations of inability and unwillingness are identified in a decentralized discourse. Regarding this, this study argues that the notion of obligation to prosecute can play a key role: a state of non-performance of obligation to prosecute can be conceived as an abusive use of power on the part of territorial or national states, thereby vesting the assessment of inability and unwillingness with certain objectivity. This provides a ground for legal discourse between territorial or national states and states exercising universal jurisdiction