An Ad Hoc Dispute Settlement Mechanism or a Harmonization Mission? A Reappraisal of Jurisprudential Fragmentation in International Investment Arbitration

Contrary to the numerous accounts of fragmentation in investment arbitration case law, this Article shows that the case law depicts a high degree of cohesion. The Article argues that jurisprudence in investment arbitration is stabilized by distinct mainstream interpretations of the key provisions of bilateral investment treaties, the main legal instrument in international investment law. The Article considers the frequently cited disagreements among arbitral tribunals in light of competing commitments to either regulatory pluralism or harmonization. It demonstrates that the vast majority of tribunals interpret bilateral investment treaties in a way that circumscribes pluralism and furthers the harmonization of the standards applicable to foreign investors. By revealing this aspect of the case law, the Article seeks to shift the debates over the legitimacy and the future of investment arbitration away from fragmentation to the main principles that have guided the harmonizing interpretations of arbitral tribunals over the past two decades