The doctrine of sources has served international law well over the past century, providing structure and coherence during a time when international law was expanding rapidly and dramatically. But the doctrine's explanatory power is increasingly being challenged. Current doctrine tells us that treaties are international law; empirical evidence, however, suggest that treaties are poor predictors of state practice. The expansion of the international community, the rise of human rights, developments in international legal theory, and the international system's need to adapt to changing circumstances, have all also put pressure on the reified role of "treaty" in identifying rules of international law.
Drawing from a number of theories developed to explain why states comply with international law, this Article proposes a new doctrine of sources focused on opinio juris and how norms come to be accepted as international law. Rather than taking for granted that a treaty reflects international law, the rules laid out in a treaty would themselves be judged by the internalized norms supporting them, either (a) in the strength and legitimacy of the process that led to the adoption of those rules, or (b) in the customary acceptance of the rule itself. This Article argues that such a revised doctrine of sources will better capture which rules are actually treated as law in the international system, blunting skepticism about international law and placing international law on firmer footing.
Harlan G. Cohen,
Finding International Law: Rethinking the Doctrine of Sources
, 93 Iowa L. Rev. 65
Available at: https://digitalcommons.law.uga.edu/fac_artchop/936