Resignation of Arbitrators and Its Examination in the Practice of the Iran-U.S. Claims Tribunal

The resignation of an arbitrator constitutes one of the grounds for the termination of an arbitrator’s mandate, as provided for in most national arbitration laws and institutional arbitration rules. However, the legal dimensions and implications of such resignation- including its effects on the parties’ rights and the arbitral proceedings- may vary depending on the arbitrator’s motives for resigning and the justifiability (or lack thereof) of those motives. For instance, the acceptance of a resignation, the method of appointing a substitute arbitrator, the possibility of continuing proceedings before a truncated tribunal (i.e., without replacing the resigning arbitrator), and even the arbitrator’s potential civil liability may be subject to differing legal determinations based on whether the resignation is deemed justified. Domestic and international arbitration laws and rules have addressed arbitrator resignations through divergent approaches, often focusing solely on the replacement of the arbitrator while neglecting broader legal and ethical challenges. These challenges include the permissibility of resignation, its acceptance, its impact on the continuation of proceedings, and the prevention of its abuse. The unique characteristics of the Iran-U.S. Claims Tribunal have rendered the issue of arbitrator resignation particularly significant within its framework. Notable in this regard are the Tribunal’s jurisprudence and its modifications to the UNCITRAL Arbitration Rules- aimed at mitigating procedural delays arising from resignations. One of the most consequential procedural rules derived from the Tribunal’s experience is the addition of Paragraph 5 to Article 13 of the UNCITRAL Rules, which imposes an obligation on the resigning arbitrator to continue participating in proceedings (post-resignation) in cases where they have already taken part in the merits hearing. This provision, known as the Mosk Rule, has introduced a distinctive mechanism to safeguard procedural integrity. This article examines the rationale behind the Mosk Rule, its legal effects in light of general principles governing arbitrator resignation and replacement, its implications on the parties’ rights, the imperative of ensuring fair and equitable proceedings, and the preservation of arbitration’s legitimacy and credibility. Furthermore, the study proposes measures to deter unjustified resignations and mitigate their adverse impact on arbitral proceedings.