The persistent objector rule in the work of the international law commission on the identification of customary international law

The persistent objector rule is a well-known but controversial mechanism for a state to exempt itself from norms of customary international law. This article examines the rule with a specific focus on the work of the International Law Commission (ILC) on the Identification of Customary International Law, through a consideration of Conclusion 15 and the commentary to it that have been adopted, as well as the ILC plenary debates on the topic. The state usage and, indeed, very existence of the rule is considered, given that this has been so controversial in the ILC and wider literature. The article further examines whether the rule rightly formed an aspect of the Commission’s work, and looks at the terminology employed in Conclusion 15. Finally, it assesses the requirements for the operation of the persistent objector rule as expressed by the ILC