Still Locked in an Ivory Tower? Some Remarks on the Relationship between the World Court and Investment Arbitration in Light of the ICJ Judgment in the case concerning Certain Iranian Assets

Not later than a decade ago, the International Court of Justice was depicted as exercising its judicial function as “locked in an ivory tower”, in so far as it had traditionally avoided any dialogue whatsoever with international investment tribunals on issues concerning substantive and procedural provisions safeguarding foreign investors. Whereas such a depiction of the Court was scratched by the 2018 Judgment in the case between Bolivia and Chile, where a clear stance was taken on the doctrine of legitimate expectations under customary international law, the Judgment rendered by the Court on 30 March 2023 in the case between Iran and the US concerning Certain Iranian Assets, constitutes a crucial step in the redefinition of the attitude of the Court vis-à-vis international investment arbitration. Indeed, even if the approach of the former is far from being entirely coherent in dealing with the arbitral case law, the ICJ has not hesitated to take straight or even sharp stances on the appropriate way of interpreting and applying pivotal standards of treatment, analogous to those couched in investment treaties. This contribution analyses the reasoning of the Court, highlighting the elements which have the potential to influence investment tribunals in the future, as well as those in relation to which the Court adopted a more cautious attitude.