The essay explores the question of why nations obey international law, a topic that has been a subject of intense debate among scholars of international law and international relations. The author, Harold Hongju Koh, reviews two recent books that address this issue: *The New Sovereignty: Compliance with International Regulatory Agreements* by Abram Chayes and Antonia Handler Chayes, and *Fairness in International Law and Institutions* by Thomas M. Franck. Both books offer sophisticated analyses but fall short of providing a comprehensive explanation for compliance. The Chayeses argue that compliance is best fostered through a "managerial model," where nations are persuaded to comply by the dynamic created by the treaty regimes they belong to. Franck, on the other hand, emphasizes the fairness of international rules as the key to compliance. However, both books overlook the complex process of institutional interaction and the internalization of global norms by domestic legal systems, which is crucial for understanding why nations obey international law. Koh traces the historical development of international law, from its primitive roots to the traditional and dualistic eras, highlighting how the concept of compliance has evolved over time. He notes that the shift from primitive to traditional international law marked a fundamental change in the conceptual thinking about transborder obligations, with sovereignty becoming a central focus. The dualistic era, influenced by positivism and utilitarianism, further challenged the traditional view of international law as a system of natural law. Koh concludes that a more complete understanding of compliance requires combining the managerial and fairness approaches with a deeper analysis of the transnational legal process. This process involves the interaction, interpretation, and internalization of international norms into domestic legal systems, which is essential for explaining why nations obey international law rather than merely conforming to it when convenient.The essay explores the question of why nations obey international law, a topic that has been a subject of intense debate among scholars of international law and international relations. The author, Harold Hongju Koh, reviews two recent books that address this issue: *The New Sovereignty: Compliance with International Regulatory Agreements* by Abram Chayes and Antonia Handler Chayes, and *Fairness in International Law and Institutions* by Thomas M. Franck. Both books offer sophisticated analyses but fall short of providing a comprehensive explanation for compliance. The Chayeses argue that compliance is best fostered through a "managerial model," where nations are persuaded to comply by the dynamic created by the treaty regimes they belong to. Franck, on the other hand, emphasizes the fairness of international rules as the key to compliance. However, both books overlook the complex process of institutional interaction and the internalization of global norms by domestic legal systems, which is crucial for understanding why nations obey international law. Koh traces the historical development of international law, from its primitive roots to the traditional and dualistic eras, highlighting how the concept of compliance has evolved over time. He notes that the shift from primitive to traditional international law marked a fundamental change in the conceptual thinking about transborder obligations, with sovereignty becoming a central focus. The dualistic era, influenced by positivism and utilitarianism, further challenged the traditional view of international law as a system of natural law. Koh concludes that a more complete understanding of compliance requires combining the managerial and fairness approaches with a deeper analysis of the transnational legal process. This process involves the interaction, interpretation, and internalization of international norms into domestic legal systems, which is essential for explaining why nations obey international law rather than merely conforming to it when convenient.