It is widely acknowledged that international organizations (IOs) indirectly affect customary international law by catalyzing and focusing State practice. But next year the International Law Commission and Michael Wood, its Special Rapporteur on the Identification of Customary International Law, are primed to address a more contentious issue: when and how IOs can directly contribute, like States, to custom.

This past summer the Commission’s Drafting Committee provisionally adopted a draft conclusion stating that “[i]n certain cases, the practice of international organizations also contributes to the formation, or expression, of rules of customary international law.” Based on Wood’s Second Report dated May 2014, three topics merit particular attention in the year ahead: 1) distinguishing State practice from IO practice, 2) scrutinizing potentially relevant types of IO practice, and 3) considering types of cases in which such IO practice might contribute to custom. (While the Drafting Committee declined to include definitions in its draft conclusions, this article defines “IO” as Wood did in his Second Report: “an intergovernmental organization.”)