A Theory of Constructive Interpretation for Customary International Law Identification

Scholars and judicial practice have long debated the nature of customary international law (“CIL”) as a source of international law, including its normative identification. Existing approaches to CIL identification largely follow the methods of induction and deduction. However, these methods are only two ends of a spectrum, and international law has yet to engage systematically with other methodological approaches that lay within this spectrum. This Article introduces a mid-spectrum approach by applying the theory of constructive interpretation to CIL identification. The Article introduces the guiding principles of constructive interpretation, examines the process of constructive interpretation in the abstract, and applies it specifically to CIL identification. The Article argues that constructive interpretation carries significant advantages over existing methods of CIL identification. It facilitates the resolution of the main two CIL impasses: (1) the relationship between general state practice and opinio juris</em>; and (2) the circularity problem of opinio juris. Finally, this Article applies constructive interpretation to the judicial assessment of CIL identification, arguing that the International Court of Justice already utilized constructive interpretation in reaching parts of its findings in the Nicaragua v. United States case. Through constructive interpretation, international law may escape the methodological divide of induction versus deduction in the process of CIL identification