Why jurisprudence doesn't matter for customary international law.

• Author: Walt, Steven

Table of Contents Introduction I. Positivism as Dicta II. Shifting the Source of Authority A. Erie's Conception of Positivism B. Mixed Conceptions of Positivism 1. Hart's Practice Version 2. Mixed Conceptions and Their Problems III. Priority and Self-Executing Law IV. Legal Argument About Customary International Law Conclusion Introduction

Customary international law is puzzling in a way treaties are untroubling. Treaties are contracts, and the source of the obligations they impose on states, as well their content, present no special legal problem. (1) If there is a puzzle about how treaties can bind states, it is a general puzzle about how contracts can legally bind promisors. By comparison, the status of customary international law is controversial. (2) Customary international law is law that "results from a general and consistent practice of states followed by them from a sense of legal obligation." (3) Because it is created by the regular practice of states, the extent of behavioral regularity required for a custom to exist is vague. Similarly, because customary international law does not have the canonical form of a treaty or statute, its content is uncertain. Even the extent to which states act merely in accordance with norms, rather than from a sense of obligation, is unknown and understudied. (4)

Customary international law has to answer a range of questions. May a state unilaterally withdraw from a treaty to which it is a party when the treaty does not otherwise provide for withdrawal? (5) Are states obligated to not arbitrarily detain people or subject them to degrading treatment? (6) May a successor state repudiate the odious debts of the preceding state? (7) Because customary international law is created by the regular practice among states, not by the states' lawmakers, (8) its legal validity is not self-evident. Three questions can therefore be asked in connection with its legal status: (1) What are the norms of customary international law governing the conduct of states and their citizens?; (2) Are states legally bound by customary international law?; and (3) Does customary international law apply domestically without incorporation by domestic law?

I will argue that there are other sorts of questions that do not need to be asked about customary international law--namely, jurisprudential ones. It is often thought that judicial recognition of customary international law depends on jurisprudential assumptions about the nature of law, legal norms, and legal validity. (9) This is a mistake. The limits of judicial reliance on customary international law are constitutional or evidentiary, not jurisprudential. (10) Jurisprudential views about law, which are analytic in character, have nothing to say about the questions posed above.

My argument follows in three steps. The first step is a claim about Erie Railroad Co. v. Tompkins. (11) Although Erie can fairly be read to require domestic authorization in order for customary international law to have domestic legal effect, the case and its reasoning do not rely on commitments to a theory of law, including legal positivism. Second, reliance on positivism has an unwelcome consequence for the binding character of customary international law. Third, conceptions of law or legal validity can ground different views about the relation between international and domestic law. Positions on the priority of customary international law are therefore determined by views about that relation, not by views on the source of its authority. Taken together, these considerations suggest that jurisprudence is not needed to answer the questions courts and other legal authorities ask about customary international law's content, the legal obligations it creates, and its domestic legal effect.

This Article is divided into four parts. Part I argues that legal positivism is irrelevant to Erie's holding that federal jurisdiction does not give federal courts general law-making power. Positivism is neither sufficient nor necessary for Erie's result and rationale. Instead, the holding rests on one or more uncertain constitutional bases. Part II describes a dilemma for those relying on legal positivism as a basis for Erie's result: dualists about international law must either conclude that customary international law does not bind governments or select a conception of positivism that preserves customary international law but is ad hoc. The domestic effect of customary international law concerns the relative priorities a legal system places on domestic and international law. Part III argues that the same conception of law can ground different views about that priority. It concludes that positions on customary international law are determined by substantive legal views about the proper relation between international and domestic law, not by the source of authority of customary international law. Part IV briefly argues, based on the conclusions in Parts I-III, that legal arguments about customary international law are unaffected by conceptual questions about the nature of law, legal authority, or the identity of a legal system.

1. Positivism as Dicta

   The requirement that customary international law must have domestic authorization to have domestic legal effect derives from Erie. According to Erie, federal courts have no power to make common law "[e]xcept in matters governed by the Federal Constitution or by the Acts of Congress." (12) Absent constitutional or congressional authorization to make law, a federal court must apply state law as decided by the state's highest court. (13) Erie's requirement of federal or state authorization is frequently thought to depend on legal positivism. (14) As a result, the domestic status of customary international law is also thought to rely on the same view about the nature of law. Customary international law is a regularity in behavior among states acting from a "sense of legal obligation." (15) Because Erie requires a legal rule to have an authoritative federal or state source, customary international law has no domestic application unless it is authorized by federal or state law.

   Legal positivism is a view about the nature of law. (16) It is a claim about what makes a norm a legal norm and makes it part of a legal system. (17) In its most general form, positivism holds that law consists of social facts of a particular sort. (18) Versions of positivism differ according to the social facts on which law depends, as well as how these facts explain law. (19) The classic form of the theory is that a state's law consists only of what its legal officials declare as binding. (20) In John Austin's version of legal positivism, law consists of the coercive orders of the sovereign and its agents. (21) This is the version that Holmes asserted in his dissent in Black & White Taxicab & Transfer Co. v. Brown & Yellow Taxicab & Transfer Co. and that Brandeis approvingly recited in Erie. (22) Positivism, if independent of Erie's holding, is superfluous to Erie and therefore also to the domestic status of customary international law. It is independent of the holding if positivism is neither sufficient nor necessary for the holding.

   It is understandable that Erie might be thought to rely on legal positivism. The opinion itself almost says as much. After basing the limitation on a federal court's power to make general common law on statutory construction and policy, Justice Brandeis came to the constitutional objection to the power. (23) The "fallacy" underlying the view that federal courts have general common law-making power, he said, is the assumption of a wrong theory of law. (24) Quoting approvingly Justice Holmes's dissent in Black & White Taxicab, Brandeis identified the assumption as the belief that there is "a transcendental body of law outside any particular State but obligatory within it unless and until changed by statute." (25) The correct theory of law instead is one which holds that "law in the sense in which courts speak of it today does not exist without some definite authority behind it." (26) This is Holmes's then-unexceptional version of legal positivism. The closeness in proximity in the opinion between this observation and the constitutional objection makes it appear that the objection has a partly jurisprudential basis. In fact, it does not. Positivism is a superfluous premise in Erie's rationale and its constitutional holding. (27)

   Positivism is insufficient for Erie's holding. Assume that positivism is true. It follows that all legally valid norms must have a federal or state source of authority. Erie's holding limiting federal judicial law-making power could still be wrong because legal positivism's truth is consistent with a variety of different constitutional roles for federal courts. Article Ill's grant of diversity jurisdiction might authorize federal courts to make independent judgments about state law. Admiralty jurisdiction is understood to give law making authority, (28) and diversity jurisdiction might do the same. Alternatively, Article III might give federal courts authority to create general federal common law: a national common law based on the same sources of law as state common law but that is neither state law nor federal law for Article VTs purposes. Different courts understood Swift v. Tyson's recognition of the judicial power to make general federal law in a diversity case in different ways. (29) If they were wrong, their error was in the interpretation of Article III, not because their interpretation was inconsistent with legal positivism. As far as positivism goes, Article III could authorize a general federal law-making power. Thus, positivism by itself does not assign any particular law-making role to federal courts. It is implausible to think otherwise, and those who think that Erie and positivism are connected in some way do not likely believe that positivism is sufficient for Erie's holding.

   More likely...