Plausibility in the Provisional Measures Jurisprudence of the International Court of Justice

In 2009, the International Court of Justice introduced plausibility as a requirement for indicating provisional measures under Article 41 of its Statute. Upon its introduction, plausibility was conceived as a test to establish that the rights asserted by applicant states might exist under international law. However, the Court subsequently developed the plausibility test into a higher standard, which requires the Court also to assess that the alleged conduct of the respondent state might breach that applicant state's asserted rights. This development has important implications for provisional measures proceedings before the Court. First, one could distinguish two aspects of plausibility, legal and factual. Second, plausibility has different functions in requests for provisional measures depending on whether the applicant state asserts rights arising under a treaty or under customary international law. Third, the Court's enquiry into plausibility could overlap with the enquiry into prima facie jurisdiction ratione materiae, although these two requirements conceivably entail different thresholds. Fourth, plausibility in provisional measures indicated in interpretation proceedings could be seen to be different from plausibility in provisional measures indicated in ordinary contentious proceedings.