Exploring International Courts’ Exercise of Incidental Jurisdiction: Towards Coherent Approaches Through Res Judicata

This article is devoted to the study of the exercise of incidental jurisdiction by international courts and tribunals. It may be concluded from the existing case law where international courts and tribunals have exercised incidental jurisdiction that there are no consistent and coherent approaches to the exercise of incidental jurisdiction now. The article also analyses alternative techniques that may be used to avoid the necessity to exercise incidental jurisdiction. It is noted that international courts and tribunals may “escape” the exercise of incidental jurisdiction due to legitimacy concerns since making determinations on incidental issues may lead to the violation of the parties’ consent to the dispute settlement procedure. The article concludes that the existence of different approaches to the issue of the exercise of incidental jurisdiction could itself result in judicial fragmentation, which, in turn, reduces the legitimacy of international courts and tribunals. In this regard, it is concluded that it is necessary to develop a coherent approach to the exercise of incidental jurisdiction by international courts and tribunals. The author concludes that a consistent approach can be developed by applying the concept of res judicata, whereby the decision of an international court or tribunal is not binding except on the parties to a case within the framework of a particular dispute. It is also concluded that decisions on incidental issues lack the force of res judicata. Therefore, it is also resumed that international courts and tribunals can exercise incidental jurisdiction without overstepping states’ consent to dispute settlement. However, res judicata may not serve as a sufficient ground for the exercise of incidental jurisdiction on its own since the role of res judicata is limited in that regard.