Table of Contents I. Introduction II. The Domestic Legal Status of Customary International Law A. Customary International Law B. The CIL Debate C. Federal Common Law D. Isolating the Important Questions III. The Domestic Legal Status of General Maritime Law A. How does Maritime Law Become Part of US Law? How Much of Maritime Law is Part of US Law? B. What are the Characteristics of General Maritime Law under US Law? 1. Supremacy 2. Preemption 3. Federal Question Jurisdiction 4. Supreme Court Review 5. Miscellaneous C. Under What Circumstances May Courts Incorporate General Maritime Law into US Law? IV. The Domestic Legal Status of Customary International Law Reconsidered
The institutional dimension of state behaviour has received insufficient attention in the international law and international relations literature. Scholars typically assume that states are unitary actors driven by discrete motivations; for most states, however, national authority over foreign affairs is distributed across many different government bodies. In the United States, for example, authority over the interpretation, implementation, and enforcement of international treaties is shared by Congress, (1) the President, (2) the federal judiciary, (3) and various state institutions. (4) Commentators who ignore these internal arrangements may misunderstand some of the complex processes that determine state behaviour on the international plane.
A new generation of political scientists and international law scholars has taken this insight to heart. Casting aside explanations of national behaviour that assume a unitary state, these scholars have begun to explore the role of domestic institutions in foreign relations. (5) They have paid particularly close attention to the activities of courts, which are thought to 'create mechanisms for ensuring that a state abides by its international legal commitments whether or not particular government actors wish it to do so.' (6) Legislators and executive officers may also contribute to international legal compliance by enforcing international legal norms against other government actors.
Building on this body of work, this article explores the significance of domestic institutions by focusing on the reception of customary international law (CIL) (7) into the domestic legal system of the United States. Because there are few international mechanisms for enforcing CIL against states, domestic enforcement of CIL is crucial to ensuring compliance. States that grant their domestic institutions significant enforcement authority will likely comply with CIL more consistently than states that withhold such authority. (8) The status of CIL in the United States legal system is thus of great importance: if CIL is binding domestic law, enforceable in domestic courts, then the United States will be more likely to comply with international legal norms; if CIL is not binding domestic law, the President and other government actors will enjoy greater discretion in deciding how to respond to international legal problems.
Despite the importance of this question, the domestic legal status of CIL is hotly contested. Until recently, it was widely assumed that CIL automatically operated of its own force as a type of federal common law (9) in United States courts. Professor Louis Henkin, for example, has written that customary international law 'is "self-executing" and is applied by courts in the United States without any need for it to be enacted or implemented by Congress.' (10) The Restatement (Third) of the Foreign Relations Law of the United States echoes this view: '[c]ustomary international law is considered to be like common law in the United States, but it is federal law' (11) which can 'supersed[e] inconsistent State law or policy.' (12) With few exceptions, the …