The number of cases discussed in this study, which is limited to natural resource exploitation disputes, confirms that common interests are ‘marching through the time-honoured institutions of the law of Treaties modelled originally along bilateralist lines’. Step by step, international judicial bodies are adapting their procedural as well as substantive rulings to accommodate the common interests they meet along the way. Not all of them are, however, walking at the same pace and in the same direction. In this book, the case law of the ICJ and six different Treaty regimes was studied to identify how international judicial bodies reconcile common interests with the rules of their specific regimes or the Treaty they have been asked to interpret.

The main questions that this book tried to answer concerned the extent to which (specialised) international judicial bodies engage with common interests and the differences or similarities between the different judicial bodies in this context. It answered these questions on the basis of a case study of natural resource exploitation disputes. In both the procedural and substantive decisions of the selected courts and tribunals, a number of similarities were found. First, at the procedural level, it was examined how common interests affect decisions on jurisdiction, standing, evidence, third party interventions and provisional measures. In the context of establishing jurisdiction, the study found that most of the discussed bodies enjoy compulsory jurisdiction. Therefore, their decisions on jurisdiction are not affected by common interests. The same is true for the ICJ, which holds on to a strict interpretation of consensual jurisdiction that is not broadened to allow common interest cases.

Thus, the fact that common interests are at risk does not make it easier or harder to establish jurisdiction. Establishing standing, however, is easier before most courts and tribunals when common interests can be invoked. Three of the discussed inter-State judicial bodies, the ICJ, the WTO DSM and the ITLOS, (implicitly) consider the common interest obligations that are included in the relevant Treaties erga omnes partes obligations and allow standing to all States in cases concerning serious violations of those obligations. The African Commission equally allows an actio popularis.