One More Time About Arbitral Challenges in Investor-State Arbitration: Overly Broad Challenges and the Boundaries of Responsible Conduct
Location:
Moot Court Room,
Old College
Date/time
Fri 25 September 2026
14:30 - 16:00
Challenges to arbitrators play an important role in safeguarding the independence and impartiality of investor-State arbitration. Yet they can also have significant consequences for the conduct of proceedings. In several prominent investor-State dispute settlement (ISDS) proceedings, parties have repeatedly sought the disqualification of individual arbitrators (or even entire tribunals). Such challenges may delay proceedings, increase costs, and, in some circumstances, place pressure on arbitrators to resign.
These concerns become particularly acute where challenges are perceived as tactical, overly broad, or based on speculative allegations. While serious questions concerning an arbitrator’s independence or impartiality must be addressed in order to preserve the integrity of the arbitral process, arbitral practice also raises a more difficult question: where should the line be drawn between legitimate scrutiny of arbitrator conduct and the strategic use of challenge procedures?
In this guest lecture, Dr. Ksenia Polonskaya examines the growing use of arbitral challenges in investor-State arbitration and the boundaries of responsible conduct by disputing parties and their counsel. Drawing on recent arbitral practice, she will consider how meritless or unsubstantiated challenges might be distinguished from challenges that genuinely respond to arbitral misconduct; whether rules of professional responsibility and legal ethics can constrain tactical challenges; and what the prevalence of such challenges tells us about the broader functioning of the ISDS system. The lecture will situate these questions within the ongoing reform of ISDS under UNCITRAL Working Group III.
About the speaker
Ksenia Polonskaya is an Associate Professor at Carleton University, Department of Law and Legal Studies in Ottawa, Canada. Her publications appeared in the Journal of International Economic Law, Journal of International Dispute Settlement, and Leiden Journal of International Law, among others. Ksenia is a co-convener of the ESIL Interest Group on Feminism and International Law. She previously served as an associate editor of the University of Toronto Law Review.
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