Compliance in International Law: The Role of Legitimacy and Effect on States’ Material Power

Why do some states follow international laws while others do not, and why is this generally accepted? To explain variation in state compliance with international law, this Article explores under what conditions international legal institutions are most effective. Using a series of case studies, this Article examines how two independent variables influence a law’s effectiveness: its legitimacy and effect on states’ material power. This Article concludes that legitimacy and a positive (or neutral) effect on a state’s material power must be present for international legal compliance. If one of these factors is absent, then a state’s compliance is unpredictable, rendering the law ineffective as related to its ultimate purpose: increasing predictability between distinct states. To evidence its claim that both variables must be present to guarantee legal compliance, this Article most critically examines China’s violation of UNCLOS in the South China Sea and Japan’s respect for the UN Security Council’s 1994 decision to impose sanctions on North Korea