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date: 03 June 2020

Five Conceptions of the Function of Foreign Relations Law

Abstract and Keywords

The comparative study of foreign relations law must first grapple with a conundrum: outside the United States, the field enjoys no wide currency or commonly accepted scope, yet the set of problems with which it is concerned arise at an interface with which all states must engage: between international law and national constitutional law. This chapter argues that the essential point of departure for effective comparative analysis is to adopt a functional approach, identifying what functions foreign relations law performs. In doing so, it identifies five different conceptions of the function of foreign relations law that shape the way in which jurists have approached the field. These conceptions are: (1) exclusionary: to separate the international from the national, taking the exercise of foreign relations out of the purview of national law; (2) internationalist: to mediate the inward reception of international law into the domestic legal system; (3) constitutional: to distribute the exercise of the foreign relations law between the organs of government; (4) diplomatic: to facilitate the diplomatic relations of the state with other states; and (5) allocative: to allocate jurisdiction and applicable law in matters concerning the exercise or enforcement of the public power of states. The chapter critically assesses the persuasive power and the potential shortcomings of each of these conceptions. Using the example of domestic cases engaging peremptory norms, it shows how the allocative approach helps to give a better explanation of when and why domestic courts intervene to enforce or apply such rules.

Keywords: foreign relations law, international law, act of state, United Kingdom, Commonwealth, diplomatic, allocative, private international law, jus cogens, peremptory norms

At the heart of the comparative enquiry to which this Handbook is devoted is a conundrum. “Foreign relations law” is not a legal term of art. It is not a synonym for public international law. Nor is it a category of the law with wide acceptance across national legal systems in contrast to, say, contract, crime or public law. On the contrary, outside the United States, the term enjoys only limited currency and no commonly accepted scope. Path-finding scholars have often remarked on the “peculiar difficulties” in trying to make sense of a field in which “the law displays much confusion of thought.”1

Despite this, the set of problems that foreign relations law investigates are ones that all states must resolve. They sit at the interface between the internal constitutional order of each state and its relations with other states within the international legal system in which all states participate. In the present era that boundary has become increasingly porous, generating legal issues of increasing frequency and intensity. Yet, as David Armitage has written, it has frequently resisted investigation, since “there has been a fundamental assumption that there were two distinct realms, called variously the internal and the external, the domestic and the foreign or (in a more legalistic idiom) the municipal and the international. That dichotomy remains perhaps the least investigated of all the fundamental divisions in our political lives.”2

By contrast, the comparative study of the relation between the domestic and the foreign is not at all neglected in the field of private law relations. On the contrary, the field of private international law retains an identity within national legal systems that is distinct from the particular categories of private law to which it applies. Despite the (p. 22) diversity of national solutions, it has long been the subject of detailed comparative enquiry and international codification.3 But the study of foreign relations law adds two dimensions to the enquiry that are not present in private cross-border legal relations. Private international law is classically understood as engaging the legal systems of two states. Whether in the assumption of jurisdiction or the determination of applicable law, its rules are concerned primarily with the horizontal relationship between two national legal systems. By contrast, foreign relations law also directly implicates a vertical legal relationship between the national legal system and the international legal system. Further, the subject matter of foreign relations law is public and therefore a part of the political life of the state both internally and in its external relations with foreign states. It is inescapably both constitutional and international.

The term “foreign relations” in this context is capable of capturing only part of the enquiry. Of course, from the vantage point of the home state, all other states are foreign. The exercise of powers within a constitution to engage outward with foreign states is a matter of foreign relations, and the department of state that conducts such relations will frequently be called a Department of Foreign Affairs. But the addition of the word “law” to foreign relations is apt to mislead to the extent that it suggests that the law in this field can be derived solely from the internal perspective of national law, treating all references to law outside the home state as foreign, whatever their source. On the contrary, the field has from the outset been concerned with the relationship between the constitution and the obligations of international law that directly bind the home state.

As a result, “foreign relations law forms that part of internal law that is most closely linked with international law.”4 It draws its sources both from international law as applicable to the relevant state and national law, in particular constitutional law, governing that state’s foreign relations.5 It must always be “double facing”:6 looking outward to the relations of the state with others beyond its borders and looking inward at the impact of the international upon the domestic sphere. This forms the starting place for any comparative enquiry. It means that international law forms a constant lodestar against which comparison of different national responses may be assessed. But it tells one little about precisely where the boundary is drawn within any particular national legal system.

The twin sources—national and international—of the legal norms that may bear upon the subject requires scholarship that straddles both fields. This poses particular difficulties in an increasingly specialized legal academy. As Louis Henkin remarked in publishing the first edition of his groundbreaking Foreign Affairs and the Constitution, “[t]he law of foreign affairs fell somewhere between the constitutional lawyer and the (p. 23) international lawyer.”7 It is not the primary focus of either field, offering neither the appeal of universality inherent in international lawyer’s endeavor,8 which aims to subject all states to a common legal system, nor the constitutional lawyer’s appeal to the internal coherence of a single national legal system.

Field definition here is not only a matter of demarcating the respective roles of internal law and international law. It is also a matter of determining a special function for the conduct of the foreign relations of a state that is distinct from other internal matters.9 What is it that is special about the conduct of foreign relations that might justify different legal rules within the domestic constitution? The special status of foreign relations has been a deeply held strain in legal philosophy that is in turn reflected in constitutional provisions and in judicial decisions. But it may also be asked whether such a distinction is consistent with the basic principles that underpin a system of constitutional government under law. Is it possible for foreign relations law to be “normalized” and subjected to the same disciplines as other applications of constitutional law?10

The argument presented here is that, in searching for what it is that is distinctive about foreign relations law, we would do better to focus on functions than on definitions. We should ask: what is “foreign relations law” for? What functions does it perform? Yet it is apparent from the many contributions to the conferences on different continents in which scholars have debated comparative foreign relations law in preparation for the present volume that there is no single answer to this question. Rather, the issues that the jurist identifies as central to their specific enquiry in turn depend upon their particular conception of the function of the field. These conceptions retain a powerful hold on the legal imagination, and thus on the way that a particular legal system may view itself vis-à-vis the rest of world, even where they do not represent actual practice.11

In order to elucidate what foreign relations law does, it is first necessary to isolate the various conceptions that operate often as unstated major premises underlying the way in which the field is characterized. These conceptions may be grouped into five categories:

  1. 1. Exclusionary. The exclusionary conception captures the idea that the function of foreign relations law is to separate the internal from the external, excluding, so far as possible, any outward facing application of the constitution, such that the external actions of the state are shielded from internal purview; concentrating the exercise of the foreign relations power in the hands of a single executive organ of (p. 24) government; and leaving the international engagements of the state with foreign states as the exclusive province of public international law.

  2. 2. Internationalist. The internationalist conception of foreign relations law embodies a strong countervailing strain: that the function of foreign relations law is to mediate the inward reception of international law into the domestic legal system, providing both the rules and processes of reception and extending also to those substantive elements of international law that are themselves directly applicable within the national legal system.

  3. 3. Constitutional. A constitutionalist focus within foreign relations law places its primary emphasis within the domestic constitution. It sees the field as concerned with the classic concerns of constitutional law—the separation of powers and the rule of law—as applied to the specific subject matter of foreign relations. That is to say, it is devoted to the distribution of the foreign relations power between the organs of government—executive, legislative, and judicial—and to the regulation of the exercise of the foreign relations power where it infringes the rights of the private individual.

  4. 4. Diplomatic. A fourth conception of foreign relations law focuses on its diplomatic functions. This approach sees the primary focus of the law in this field as facilitating the external relations of the state with foreign states. This is partly a matter of positive rules of law (international and domestic) that facilitate the intercourse of states. It also calls for a focus on state practice and for the discretionary consideration of diplomatic relations in the application of positive law.

  5. 5. Allocative. A fifth conception of foreign relations law views its function as allocative: as a set of rules of jurisdiction and applicable law. Such rules allocate competence and determine which law (whether national or international) is to be applied to determine issues concerning the external exercise or enforcement of the public power of states. In this way foreign relations law performs a function akin to that of private international law within the different context of public law.

Characterizing the different approaches to foreign relations law in this way is not meant to suggest that any particular legal system adopts only one of these conceptions. On the contrary, as will be seen, traces of each of these conceptions may be found in many different legal systems, despite otherwise major differences in their respective legal traditions.

I. The Exclusion of Foreign Relations from Domestic Law

The roots of the idea that the constitutional state exists to protect itself and its citizens from the chaos of relations beyond its border run very deep in political philosophy. (p. 25) This is expressed most trenchantly in Hobbes’ proposition that “in all times, Kings and Persons of Soveraigne authority, because of their independency, are in continuall jealousies, and in the state and posture of Gladiators; having their weapons pointing, and their eyes fixed on one another.”12

The conclusion drawn by John Locke from the state of nature that otherwise exists outside an organized constitutional state is that the public power of dealing with relations outside the state—the “security and interest of the publick without”—must be concentrated in the single hands of the executive.13 Locke coined the term “federative” for this distinct element of the executive power, which “contains the Power of War and Peace, Leagues and Alliances, and all the Transactions, with all Persons and Communities without the Commonwealth.”14 He argued that the exercise of this power “is much less capable to be directed by antecedent, standing, positive Laws…and so must be left to the Prudence and Wisdom of those who hands it is in, to be managed for the publick good.”15 Any division of the federative power internally “would be apt sometime or other to cause disorder and ruine.”16

In English law, the powerful influence of Locke’s idea of the concentration of the foreign affairs power in the hands of the executive is felt in the continuing emphasis on the prerogative as the legal source of the foreign affairs power. For Dicey, the prerogative power, defined as “the residue of discretionary or arbitrary authority, which at any given time is legally left in the hands of the Crown,”17 had a particular application to “all foreign affairs.” Though Ministers and not the Monarch in fact exercised this power, they did so “free from Parliamentary control.”18

The idea that the international and the domestic are two distinct realms also justifies dualism in the relationship between the treaty-making acts of the executive on the international plane and the sovereignty of Parliament to prescribe the law of the land. If treaties can have no effect within domestic law, Parliament’s legislative supremacy within its own polity is secure. If the executive must always seek the sanction of Parliament in the event that a proposed action on the international plane will require domestic implementation, parliamentary sovereignty is reinforced at the very point at which the legislative power in engaged. The significance of the “fundamental principle of the Constitution that, unless primary legislation permits it, the Royal prerogative does not enable Ministers to change statute law or the common law” was underscored as recently as 2017 in the context of the litigation over the United Kingdom’s decision to withdraw from the European Union.19

(p. 26) The exclusion of foreign affairs from the domestic realm also limits the scope of the judicial role in foreign affairs. Contemporary British and Commonwealth courts have accepted that the exercise of the foreign affairs power is derived from the prerogative20 and that this limits the scope for judicial review.21

The state is conceived as a unity in all its relations without. Locke saw it as “one Body…in respect of all other States or Persons out of its Community.”22 One conclusion drawn from this unity on the international plane has been that there has to be a corresponding internal unity in foreign relations matters between the organs of state, since the “State cannot speak with two voices…the judiciary saying one thing, the executive another.”23

The idea of foreign relations as a zone of nonlaw within the municipal legal system finds its highest expression in the doctrine of act of state, defined by Harrison Moore as an act which “whether it be regulated by international law or not, and whether the acts in question are or are not in accord with international law, is not a subject of municipal jurisdiction.”24 In the application of this doctrine, the executive retains the ability to exclude from domestic adjudication some common law claims in respect of its actions affecting foreigners abroad (at least in situations of armed conflict).25

A cognate doctrine in U.S. jurisprudence is that of the political question: that “[t]he conduct of the foreign relations of our Government is committed by the Constitution to the Executive and Legislative—‘the political’—Departments of the Government, and the propriety of what may be done in the exercise of this political power is not subject to judicial inquiry or decision.”26

The notion that foreign affairs are excluded from the municipal realm is not unique to the common law tradition. On the contrary, marked elements of an exclusionary doctrine may also be found in the legal systems of some civil law states, notably those in the French tradition.27 In France, the theory of the acte de gouvernement traditionally limited the extent to which the administrative courts would review the international or diplomatic activities of the executive.28 Though the Conseil d’Etat has moderated this (p. 27) exclusionary doctrine by developing the notion of an acte detachable,29 it remains a viable plea.30 In Italy, the equivalent doctrine (atto politico) precludes the court from reviewing the manner in which political decisions of the state that are directed toward the international plane are taken and implemented.31

The imprint of the exclusionary doctrine continues be found in the constitutional thought of many states. The exclusionary doctrine captures two essential structural features of foreign relations law that continue to be of contemporary relevance. The first is the sovereign equality and independence of states, which in turn supports the independent domestic jurisdiction of states. The world is divided into separate national legal systems each of which has the capacity to determine for itself its relations with others.32 The second is the central importance of the executive branch within constitutional systems in the actual conduct of foreign relations. Only the executive may act on the international plane, representing the state in its relations with other states. When it does so, the executive is not necessarily directly engaging rights and duties within the domestic sphere. This fact in turn has implications for the roles of the legislative and judicial branches.

However, to the extent that the exclusionary doctrine seeks to create a zone of nonlaw filled only by executive discretion, it fails to explain other key features of the legal regulation of foreign relations. First, it leaves out of account the real impact of international law upon the practice of states, an impact that falls most directly on the executive. The exclusionary doctrine put at its highest suggests that the exercise of the executive function in foreign affairs is a pure matter of discretion unbound by legal constraints.33 Yet both the historical record34 and contemporary practice continue to demonstrate the importance of the point made by Bethlehem that “[l]egality is paramount.…Governments may stand or fall by reference to considerations of legality.”35 The impact of international law on the practice of states has both an external and an internal aspect. Externally it constrains and in turn determines the legality of the external exercise of state power on the international plane. Internally, it operates to (p. 28) constrain the decisions of the executive. This is no less regulation according to law, whether or not it is also subject to domestic judicial review.

Second, the exclusionary doctrine does not explain essential aspects of the dynamics of the relations between states. It presents a one-sided view of foreign relations as concerned only with the position of the home state. This is, as Crawford has put it, a distorted conception of international law through “the sound of one hand clapping,”36 since it fails to take account of the fact that international relations and in turn international law are made through the relations of two or more states, each with their own distinct interests. Nor can the relations between states be confined to the international plane and excluded from domestic purview. On the contrary, the legal relations between states involve multiple interactions at the domestic level, including in diplomatic relations and where states sue or are sued in the domestic courts of other states.

Third, the exclusionary doctrine does not account for the constitutional role of the judiciary in the protection of the individual from the abuse of executive power. The separation of powers exists not as a license for executive impunity, but in order that the judiciary may hold in check the power of the executive branch, where the latter’s actions infringe the legal rights of individuals. This is a basic attribute of the rule of law in constitutional systems. Since executive actions abroad are as susceptible of infringing individual rights as its actions at home, any theory of foreign relations law must hold in balance the executive’s right of action with a correlative protection of the individual.

Fourth, the exclusionary doctrine fails to explain the multifaceted role of international law within national legal systems, including those that adhere to a dualist approach. Why should the domestic judiciary concern itself at all with international law if the latter regulates only the world outside? Yet there is abundant evidence of reference to international law in domestic judicial decisions across a broad spectrum of different national legal systems.

II. The Domestic Reception of International Law

Whatever may be its continuing salience, the exclusionary approach does not explain a critically important means by which national legal systems mediate their relationship with the international sphere, namely, through rules of reception and recognition of international law. “Each legal system has its own rules of recognition: that is what it is to be a legal system.”37

(p. 29) The response of many scholars invited to participate in the present comparative exercise has been to view foreign relations law through the lens of the domestic reception of international law. Karen Knop refers to this in her introductory essay here as “the inward-looking perspective of international law in domestic law.”38 This question in turn invites separate consideration of (1) the national mechanisms for the conclusion and incorporation of treaty obligations;39 and (2) the domestic law status of customary international law, including jus cogens norms.40

These issues fit the foreign relations law rubric not simply because they concern the interaction of international and national law. They also engage the functions of the organs of government within a constitutional state. The process for the ratification and incorporation of treaties concerns the relation between the executive and the legislature. The status of customary international law within the domestic legal system engages the function of the judiciary in the direct application of international law as a source of the applicable law.

The way in which particular legal systems determine the status and applicability of international law is not solely determined by the extent of adoption of an exclusionary approach: by whether the state regards itself as “dualist”—excluding the direct application of international law norms that have not been incorporated by Parliament into the domestic legal system. As Verdier and Versteeg conclude in their comparative survey: “the traditional monist-dualist distinction, which originally arose out of theoretical debates on the nature of international law, has limited value for the purpose of classifying actual legal systems or examining their policy and normative implications.”41

This point is striking in the case of common law systems that have been traditionally treated as dualist. This description does not account for the direct application of customary international law within a common law legal system. Such a role may be traced to Blackstone’s famous dictum:

In arbitrary states [international] law, wherever it contradicts or is not provided for by the municipal law of the country, is enforced by the royal power: but since in England no royal power can introduce a new law, or suspend the execution of the old, therefore the law of nations (wherever any question arises which is properly the object of its jurisdiction) is here adopted in its full extent by the common law, and is held to be a part of the law of the land.42

Blackstone’s point here is that the judiciary has a unique function within a constitutional state to apply international law when it is confronted with an issue for the (p. 30) resolution of which international law is the applicable law. This principle originated in cases that directly affected foreign relations being concerned with the immunities of foreign states and diplomats.43 But the power of the judiciary to apply customary international law directly has a much more general application, since, as a broad comparative analysis has shown, “in virtually all states, [customary international law] rules are in principle directly applicable without legislative implementation.”44

The status of treaties within the domestic legal system is a matter of constitutional design that may also implicate the role of the courts. A provision that “all Treaties…shall be the supreme Law of the Land”45 has broad implications not only for the sources of law within the domestic legal system but also for the power of the judiciary to determine the validity of other provisions of the law vis-à-vis the other organs of government.46

The general rules of recognition and incorporation of international law adopted within a particular national legal system affect the sources of law applicable to foreign relations questions that may come before the courts, because they determine to what extent and in what circumstances the courts may refer directly to international law rules. The internationalist approach to foreign relations law may, at its most expansive, seek to restate large parts of the substantive provisions of international law that are of direct application in the relevant state.47

The internationalist conception of foreign relations law is valuable precisely because it directly confronts the other part of the equation, the regulation of which is the central function of the field. In contrast to the exclusionary approach, it does not cast international law into a black hole of matters of no legal relevance to the domestic legal system. It enables consideration of the rules of international law that take into account the interests of other states as well as that of the home state. It also captures an important part of the practice of national courts in the direct application of international law to the decision of the claims of individual litigants before them.

However, an exclusive focus on the reception of international law may also leave important functions of foreign relations law out of account. In the first place, foreign relations law must accommodate the reception of international law within the constitutional constraints of a national legal system. A national court is bound to interpret its function within its own constitution. Constitutional doctrines that may (p. 31) limit the extent to which a court may properly give effect to international law are not to be summarily dismissed as “evidence of political limitations of the exercise of judicial independence,”48 since “the domestic interpretation of international law is not simply a conveyor belt that delivers international law to the people.”49 Foreign relations law has to explain when and why international law is to be received and what function it is to perform within the domestic legal system.

In the second place, the rules of recognition that enable international law to be applied or taken into account in national legal systems play a much wider role than the conduct of foreign relations. The engagement of states in treaty-making now covers almost every aspect of human activity. This means that the contexts in which national legislatures and courts have had to examine the relevance of treaties reaches deep into almost every aspect of the domestic legal system. The influence of international law within the contemporary domestic sphere is pervasive. It affects many issues between citizen and state that are otherwise purely domestic, and has broad implications for the process of judicial interpretation.50

An internationalist conception captures more than is strictly necessary for the resolution of issues arising within domestic legal systems concerning the external exercise of public power in the relations between states, which remains the central concern of foreign relations law. These issues have to be disaggregated from the broader questions of the relation between national and international law to facilitate effective comparison and analysis.

III. Foreign Relations Law as Constitutional Law

A third way of looking at foreign relations law is to see it as a branch of constitutional or public law: as principally concerned with regulating the distribution of the foreign relations power between the organs of government. In this way, foreign relations are conceived primarily as an issue of internal governance, albeit that the subject matter of the enquiry concerns relations with the world outside.

To some extent this is an inevitable consequence of the need in constitutional states to organize and regulate the exercise of this particular type of power. As Hersch Lauterpacht put it, “limitations upon the freedom of judicial decision, far from amounting to a (p. 32) suspension of the rule of law, are the expression of a differentiation of functions, which for reasons of obvious expediency is unavoidable in the modern State.”51

The fact that foreign relations law must concern itself with the internal as well as the external, means that the unity of the state, a fundamental principle in international law,52 cannot be simply transposed into the domestic framework, since “the identification of the judicial and other organs of the state with the state itself is a principle of international law. But it has no place in the domestic jurisprudence of the state. The legal relationships of the different branches of government depend on its internal constitutional arrangements.”53 For this reason, where a state organizes its internal constitutional arrangements in a manner that aims to separate the executive from the legislative and the judicial function, it is often a matter of great moment, in principle as in practice, to determine which branch holds particular elements of the foreign relations power and to what extent this may effectively be checked by other branches.

The allocation of such powers between the executive and the legislature may be a matter of conscious constitutional design, as, for example, in the case of the U.S. Constitution, which confers power upon the president “by and with the Advice and Consent of the Senate, to make treaties.”54 This “intermixture of powers” was deliberate, since, as Madison recognized, “[t]he qualities elsewhere detailed as indispensable in the management of foreign negotiations, point out the Executive as the most fit agent in those transactions; while the vast importance of the trust, and the operation of treaties as laws, plead strongly for the participation of the whole or a portion of the legislative body in the office of making them.”55

A shared responsibility between the executive and the legislature may also be found in other constitutional systems.56 In Commonwealth states, the role of Parliament in the treaty ratification process has been significantly extended in recognition of the significance of treaties in the law making process.57 There has been a parallel debate about the role of the legislature in the decision of the state to engage in armed conflict.58

(p. 33) A constitutional approach also engages the proper role of the judiciary in foreign relations matters.59 It seeks to explain the doctrines applied by the courts in terms of the proper province of the judicial function vis-à-vis the executive. In this way, the courts may either find foreign relations cases nonjusticiable as “beyond the constitutional competence assigned to the courts under our conception of the separation of powers;”60 or adjudicate them where they engage private rights or public law duties cognizable within the domestic legal system.

A core element of the judicial function in a constitutional state is the protection of the individual against the abuse of the executive power of the state, whether such power is exercised internally or externally. The constitutional approach can therefore also serve to articulate a common public law spine to the state’s conduct of its foreign relations where such conduct trenches upon the fundamental rights of the individual—a spine that links national law with international law. This link is particularly apparent in states that have given domestic effect to international human rights norms, making them domestically enforceable and at the same time affording individuals a subsequent right of recourse to an international tribunal, as in the case of the European Convention on Human Rights.61

More generally, a focus on the shared elements of public law and public international law can serve what F. A. Mann has called “the ultimate unity of the law”62 by promoting the shared disciplines of constitutionality at both the national and the international level. This is a particular feature of the German approach, which both seeks to subject the foreign relations power to public law disciplines at the domestic level and has developed the concept of the constitutional function of international law.63 The consequence of this approach for the domestic judicial function is that in general foreign affairs is not excluded from judicial review. Rather, the courts determine such cases through the substantive interpretation of constitutional standards of control. Nevertheless, the judiciary may be expected to exercise judicial self-restraint on the merits in such cases, according the executive a higher degree of discretion in light of the nature of the issues.64

A constitutional conception of the primary function of foreign relations law may still, when translated into comparative law terms, result in an outward-facing focus: on those aspects of the distribution of powers internally within constitutional systems that concern the state’s international engagements. Hathaway argues that a constitutional focus to the comparative enquiry may in this way benefit our understanding of international law since “it is the states themselves that decide when and how they (p. 34) will consent—and they do so through their own domestic legal and political institutions. Accordingly, examining domestic institutions that states use to create international law is essential to our understanding of international law.”65

But an exclusive focus on the internal constitutional dimension of foreign relations law runs the risk of leading to an inward focus in which “international law is taught as just another aspect of the domestic public law.”66 This is particularly so where the foreign relations issues and the international law rules that they engage are subordinated to the study of “national security law,” a field that has achieved particular prominence since 9/11 and which prioritizes the study of the protection of the nation according to principles of national law over international law norms.

At its most expansive such an approach can seek to rewrite the international relations of a particular state with the international community in exclusively domestic terms,67 or to serve as a justification for the exercise of broad executive power abroad.68 Such an interpretation of the function of foreign relations law can engender isolationism, cutting off the foreign relations law of a particular state from the engagement with other states and with the system of international law, which is the other side of the relationship that it exists to regulate.

IV. The Diplomatic Function of Foreign Relations Law

The fourth conception of foreign relations law stands in contrast to the constitutional model. It rather sees the principal function of foreign relations law to be diplomatic, that is to say: to promote the conduct of foreign relations between states. Such a conception views foreign relations law as operating in an horizontal dimension, neither inward-looking nor outward-looking, but rather reflecting the actual conduct of diplomatic relations, which operates in both directions, with each state seeking through those relations to promote its own foreign policy objectives.

Karen Knop has illuminatingly suggested that there may be different conceptions of the function of diplomacy itself at work here: whether it is conceived as “an instrument and background condition of foreign policy,” as “including the substance of foreign policy,” or “as simply describing relations conducted through negotiations.”69 However (p. 35) the practice of diplomacy is itself conceived, it was early linked with foreign relations law. Early works in the field sought to capture this link, by expounding both the law applicable to the conduct of diplomatic relations and the practice of diplomacy by the relevant states.70 In present times, much of the law relating to the conduct of diplomatic relations has been codified in conventions of wide acceptance, such that it has become international law properly so called.

The immunity of states from the domestic jurisdiction of other states is another key part of the conduct of bilateral relations between states that is regulated by international law. Immunity is a rule of customary international law rooted in the practice of states.71 State immunity “derives from the sovereign equality of States, which, as Article 2, paragraph 1, of the Charter of the United Nations makes clear, is one of the fundamental principles of the international legal order.”72 The rules of immunity also serve a diplomatic function, since they “promote comity and good relations between States through the respect of another State’s sovereignty.”73

Nevertheless national legislatures and national courts retain a vital function in determining the precise scope of the immunity of states. The law on state immunity is derived from international law, but it must be interpreted and applied by national courts. State practice differs widely in the extent to which states have accepted exceptions to the principle of immunity.

Diplomatic relations may also be engaged in the protection of individual rights. International law recognizes the right of states to exert diplomatic protection where the actions of foreign states affecting the nationals of the home state give rise to an international delict.74 Such a right is vindicated on the international plane.75 But each state must also resolve for itself, as a matter of domestic law, the extent to which the state has a duty to protect its nationals, when they are subject to gross abuses of their rights at the hands of a foreign state.

Beyond the law of diplomatic relations and immunity stricto sensu, a conception of foreign relations law as diplomatic in function may have wider implications for the approach of national courts in deciding cases that engage the interests of foreign states and, in turn, may affect the foreign relations interests of the home state. The idea that “comity” should guide the extent to which each sovereign state takes account of the interests of other states may be traced to the seventeenth-century Dutch jurist Ulrich Huber.76 In common law legal systems the notion of comity has exerted a powerful (p. 36) influence across a wide range of cases involving foreign elements.77 Though used in a number of different senses, it is frequently deployed to explain the court’s view that the interests of a foreign state must be taken into account.

A particular manifestation of this is the foreign act of state doctrine, expressed in the general proposition that “the courts of one country will not sit in judgment on the acts of the government of another done within its own territory.”78 Though subject to sustained criticism and much qualified by later decisions, the idea that the judicial function may properly be limited by diplomatic considerations of comity between nations still exerts a powerful hold in common law jurisprudence.79

The diplomatic conception of foreign relations law sees foreign relations law as not merely the concern of the constitution of one state. It performs the important function of focusing attention on the application of the law governing the relations between states when such issues arise within domestic legal systems.

On the other hand, the diplomatic conception has shortcomings of its own to the extent that it substitutes general references to comity or foreign act of state for a proper analysis of “the issues that arise in each case at a more particular level than is achieved by applying a single, all-embracing formula.”80 The doctrine of foreign act of state does not form part of international law, so as to preclude courts generally from reviewing the legality or effectiveness of foreign acts of state—a proposition confirmed in both German81 and French law.82 Rather, it is necessary to analyze what law is applicable to the claim before the court, which may, depending upon the nature of the issue, be the law of the forum, foreign law, or international law.

V. The Allocative Function of Foreign Relations Law

A fifth conception of foreign relations law is that it performs an allocative function: providing a set of rules that allocate jurisdiction and determine applicable law in cases involving the external exercise of the public power of states.83 It does so in three dimensions: (1) between the organs of government within the national constitution; (2) between states; and (3) between the municipal and the international plane.

(p. 37) What is meant by an allocative function? Within the constitutional order of a nation-state, the idea of allocation serves a similar function to that of the distribution of the foreign relations power between the three organs of government: executive, legislative, and judicial. In states where the conduct of foreign relations has, as a matter of traditional doctrine, been seen as highly concentrated in the exercise of prerogative power by the executive, asking where the exercise of a particular power is allocated facilitates clearer analysis than blanket doctrines of judicial exclusion, deference or “speaking with one voice.” It distinguishes, for example, matters that are plainly within the competence of the executive, such as the recognition of states, from matters concerning the protection of the rights of the individual affected by an exercise of the foreign relations power, where the judiciary may have power to intervene.

If this were the only dimension of allocation, one might reasonably conclude that a modern approach to constitutional analysis can perform the same task. However the resolution of foreign relations law issues requires the analysis of two other dimensions that lie outside the state: its relations with other states and its engagement with public international law. The first of these describes a horizontal dimension of allocation that is especially applicable to questions of legislative jurisdiction and state immunity. The second describes a vertical dimension, namely the question whether a particular issue is in fact properly capable of resolution within the national legal system at all or must rather be decided on the plane of international law or subject to its rules.

These considerations require an internationalist perspective. Why then is it necessary to interpose an intermediate set of rules of allocation between public international law, whose central concern is the relations between states, and the substantive rules of municipal law? Undoubtedly, the outlines of the solutions to problems of foreign relations law are supplied by public international law. But a law of foreign relations requires more than the simple transposition of such principles. An internationalist approach that seeks to address the external dimensions of foreign relations law solely through rules of reception of international law into the municipal legal system cannot address when reference is to be made to international law in the resolution of specific issues before the domestic court or when the domestic court of the forum must defer to the international legal system to determine the dispute.

Nor are the answers to these problems sufficiently to be found from an internal examination of the reach of municipal laws, since they engage the interaction of different legal systems (international law and the laws of other states). It is necessary to work out a much more fine-grained set of rules consistent with international law principles in order to provide workable solutions to current problems. In short, the allocative approach enables the task done for cross-border private law relations by the rules of the conflict of laws to be done for public law as well.84

One might object that such an approach transposes a methodology from private international law that is not capable of adaptation for public law issues. Indeed (p. 38) private international law has itself traditionally sought to exclude direct consideration of public law issues from its scope.85 Indeed, the prime function of choice of law in private international law has no direct analogue in public law matters. Neither the exercise of the external public power of the home state nor the treatment in domestic law of the foreign state necessarily involves the systematic application of choice of law rules leading to the application of either domestic or foreign law. Moreover, determinations of jurisdiction and applicable law in this sphere are not, as in private international law, primarily two-dimensional: determining horizontally the application of two competing systems of municipal law. They may also involve a three-dimensional vertical consideration: both of the application of public international law and its systems of dispute settlement; and internally within the state, determining the competence of the respective organs of government.

Seen in this light, an allocative conception of foreign relations law is not a mere transposition of a conflicts methodology developed for private law cross-border relations into the field of public law. Rather, it is an attempt to explain and synthesize key elements of a number of the other conceptions of foreign relations within a single coherent framework.

Such an approach provides a clearer explanation of the issues involved in determining the scope of prescriptive jurisdiction in public law cases.86 An approach that seeks to analyze the reach of a domestic statute without reference to the interests of other states could, if unconstrained in its extraterritorial reach, result in serious conflict with the reserved domestic jurisdiction of other states. At the same time, a simple reference to the presumption of territoriality will not on its own suffice to determine what is the relevant connection to the territory, nor to deal with conduct that spans national borders and is “both here and there.”87 Principles of international law delimit the outer boundaries of permissible exercises of state jurisdiction. But on their own they do not resolve the interactions between the public laws of different states, when the exercise of jurisdiction overlaps. Nor are the international law principles of jurisdiction capable of resolving the liability of the state to individuals affected by its conduct when it has in fact already acted outside its own territorial borders.88

By contrast, an allocative approach asks how to balance the jurisdiction of the home state with the reserved jurisdiction of other states. Common law courts frequently invoke “international comity” in order to explain a process that is more accurately understood as an identification and application of the factors that connect given (p. 39) conduct to a foreign state or to the home state, so as to identify whether there is a “sufficiently close connection to justify [the home] state in regulating the matter and perhaps also to override any competing rights of other states.”89

So, too, the doctrines of state immunity and the foreign act of state have been explained as performing an allocative function. Hazel Fox writes that a principal function of the rules of state immunity is to serve “as a method of allocating jurisdiction between States relating to the prosecution of crimes and the settlement of claims by private litigants relating to State activities.…[I]t serves both as a sorting device between competing jurisdictions and as a holding device by which confrontation between States is avoided.”90 Mann argued that “the foreign act of State ought to be recognized and allowed effects…if it is done subject to or is recognized by that legal system which governs the legal relationship concerned.”91

VI. Application in Cases Engaging Jus Cogens Norms

Analyzing foreign relations law problems as ones of allocation also provides a more coherent explanation for long-standing apparent inconsistencies in the application of international law at the domestic level, including in the hardest cases, such as the application of jus cogens norms by national courts.

Why, for example, was it that a peremptory norm could be applied directly to defeat a claim of immunity in the criminal claim against Pinochet, but not in subsequent civil claims brought before national courts?92 In this enquiry “the jus cogens nature of the rule alleged to have been infringed does not provide an automatic answer.”93 Rather it is necessary to disaggregate the general issue depending upon the proper extent of jurisdiction and applicable law.

Where the peremptory norm speaks directly to the responsibility or the rights of the individual, the forum court may be able to give effect to it, provided that international law accords that court jurisdiction. So in Pinochet the House of Lords was concerned with a criminal application for extradition of Pinochet on charges of, inter alia, torture. (p. 40) The House held that “[t]he jus cogens nature of the international crime of torture justifies states in taking universal jurisdiction over torture wherever committed.”94 But the fact that an assumption of universal jurisdiction may be justified was not sufficient to answer the question whether the exercise of such jurisdiction was barred by another set of rules of customary international law: those relating to state immunity. On this crucial question, the decisive factor in the reasoning of the House was implied waiver by treaty. States (including in this case Chile) that had become party to the Convention against Torture (CAT) had implemented the prohibition on torture by expressly conferring jurisdiction on the state where an alleged offender was found and, by consenting to its exercise, necessarily waived immunity.95 Once the House had decided that international law was the law applicable to the issue before it, the distinction (otherwise so fundamental to the reception of international law in the constitutional conception within a dualist state) between custom and treaty was simply incapable of addressing the issue. The House had to apply international law as a whole—custom and treaty—to determine whether immunity had been waived as a consequence of the treaty’s conferral of universal jurisdiction upon national courts.

By contrast, the jus cogens character of the norm is not in itself sufficient to confer jurisdiction upon a national court in a civil claim against a foreign state or its officials. This would be to conflate the content of the substantive law with the prior question of whether the court seised has jurisdiction. In Jurisdictional Immunities, the International Court of Justice specifically held that “the rules which determine the scope and extent of jurisdiction and when that jurisdiction may be exercised do not derogate from those substantive rules which possess jus cogens status.”96 The common law courts have taken the same approach. So, in Jones v. Saudi Arabia, the House of Lords held that a civil claim of torture against a foreign state is barred by state immunity, despite the jus cogens nature of the norm. It found that there is no waiver of immunity in the CAT in civil cases akin to that in criminal cases that could operate to confer jurisdiction on the forum court, as states did not agree to confer universal jurisdiction upon each other’s courts for civil claims, as they had in criminal cases.97 An essential step in the reasoning in Jones is that the state asserting immunity is assuming state responsibility for the act. It follows from this that, if there is a denial of justice in the foreign state, its responsibility will be engaged on the international plane.

The position is different where the nature of the norm itself is one that can only properly be adjudicated on the international plane, because it concerns the relations (p. 41) between states. A national court does not adjudicate such a claim because the enforcement of the rule is allocated to the international plane. This is the case where the claim engages the rule against the use of force. As Lord Hope explained in Gentle: “The issue of legality in this area of international law belongs to the area of relations between states.”98 In Margaret Jones, the House of Lords was concerned with whether the prevention of an act of aggression could constitute a defense to a criminal charge. The crime of aggression could not be invoked before a domestic court, since it is “intrinsically and inextricably linked to the commission of aggression by a state,”99 which involves the actions of the states on the international plane.100

Where a national court does have jurisdiction and is called upon to apply foreign law to a civil claim, it may be required to give effect to international law, where the rule of foreign law offends a peremptory norm. In allocative terms, this is because the peremptory norm is applicable as a super choice of law rule. In Oppenheimer v. Cattermole, the House was faced with determining the applicability of a Nazi decree that had deprived Jews of their German citizenship on emigration. It held that ordinarily the court must give effect to the jurisdiction of a foreign state over its own nationals and assets situate within its territories.101 But the law in question in this case was different. As Lord Cross put it, such a law “constitutes so grave an infringement of human rights that the courts of this country ought to refuse to recognise it as a law at all,” it being “part of the public policy of this country that our courts should give effect to clearly established rules of international law.”102

The same principle was extended to other breaches of the mandatory provisions of international law in Kuwait Airways.103 In that case, the House held that, although Iraqi law was otherwise applicable to the claim, an Iraqi decree purporting to validate all acts arising from Iraq’s invasion of Kuwait could not be applied. It was contrary to the express provisions of a UN Security Council resolution.

The common feature of both of these cases is that the norm of international law in question was one that has a peremptory character—either in customary international law (as in the case of rule against discrimination in Oppenheimer) or by virtue of Article 103 of the UN Charter. It is this special feature that distinguishes both of these cases from the ordinary rule (referred to under the rubric of the foreign act of state doctrine) requiring the court to give effect to the jurisdiction of a foreign state within its own territory, a rule frequently applied by English courts to cases of expropriation in foreign states.104 The ordinary rule is premised upon the international law rule of the sovereign equality of states. But the forum court is entitled to decide that the obligation of respect owed to the act of the foreign sovereign is dislodged by a higher norm within the international legal system that claims peremptory application.

(p. 42) So too the foreign act of state doctrine finds its limits where the officials of the home state are sued for their alleged complicity in the acts of foreign states outside their own territory, where those acts constitute breaches of peremptory norms. This point came to the fore in the recent judgment of the U.K. Supreme Court in Belhaj v. Straw,105 in which a British Minister and high officials were sued for their alleged complicity in acts of torture committed by U.S. officials outside the territory of either state.

One way of explaining the foreign act of state doctrine, developed by Bjorge and Miles in their chapter for this Handbook,106 is through a constitutional law analysis: that the doctrine is primarily concerned with the separation of powers between the judiciary and the executive within the domestic constitutional order. Undoubtedly such a conception provides part of the answer. However, on its own, this does not explain (as those authors conclude107) when the courts will find the claim to be admissible and when not. When should the constitutional function of the judiciary in the protection of the rights of the individual take precedence over the constitutional power of the executive to conduct foreign affairs? A constitutionalist conception cannot in any event address all dimensions of the issues raised by the justiciability of claims involving the conduct of foreign states, since of their nature these also engage both the external relations of the home state with foreign states and the role of public international law.

Lord Sumption in his minority judgment sought to explain the distinction by setting up the jus cogens character of the norm as an exception to what he saw as the ordinary rule requiring judicial abstention in all other cases of what he termed as “international law act of state.”108 Such an approach, however, conflates jurisdiction with applicable law, by treating the substantive law character of the norm as the determinant of jurisdiction.109

An allocative approach analyzes the issue more directly, by asking, as Lord Mance did in his leading judgment, why the English Court, which undoubtedly had jurisdiction over the British government officials, should not require them to answer for their alleged complicity in such serious breaches of fundamental norms.110 No deference to a foreign state can derogate from the principle that officials are answerable before their own courts and may not escape liability at home for fundamental breaches of peremptory norms simply because they are complicit with the illegal acts of the officials of other states. Such claims are properly allocated to the courts of the home state. Otherwise those claims “could not be pursued anywhere in the world.”111

(p. 43) The cases in which the foreign act of state doctrine has justified the abstention of the domestic court are not explained simply on the basis, as Lord Sumption thought, that all acts of a foreign state outside its own territory are nonjusticiable (unless falling with his exception). Rather, they concern situations in which the issue engages a rule that of its nature can only be determined on the international plane and according to public international law, such as a boundary dispute between two sovereign states112 or the liabilities of states for the debts of an international organization of which they were members.113 Such cases are allocated to the international plane.

VII. Conclusion

It is remarkable that the relation between public international law—the legal system that all states have in common—and national legal systems in the exercise of foreign relations has to date proved so resistant to comparative investigation. One reason for this has been that the approach that one takes depends upon one’s conception of the function of the law in this field. Differences in starting points can result in whole elements of the field being excluded from the enquiry as legally irrelevant. It is only by exposing those conceptions to critical examination that legal scholars can move beyond a mere exchange of differences and begin to analyze the actual legal problems that arise.

Seen in this light the present comparative investigation offers the prospect of saving the study of foreign relations law from isolationism. Instead it may promote engagement between states in the exploration of a common issue of great importance in our times: the regulation of the interface between international law and national constitutions in the control of the external exercise of public power.


(1) Francis A. Mann, Foreign Affairs in English Courts vi (1986).

(2) David Armitage, Foundations of Modern International Thought 10 (2013).

(3) Alex Mills, The Confluence of Public and Private International Law (2009).

(4) Thomas Giegerich, Foreign Relations Law, in Max Planck Encyclopedia of Public International Law (last updated 2011).

(5) Restatement (Third) of the Foreign Relations Law of the United States § 1 (1987).

(6) The writer is indebted to David Dyzenhaus (University of Toronto) for this illuminating expression.

(7) Louis Henkin, Foreign Affairs and the Constitution viii (1972) (preface, reproduced in the second edition in 1996).

(8) But see Anthea Roberts, Is International Law International? (2017).

(9) Helmut Aust, Foreign Affairs, in Max Planck Encyclopedia of Comparative Constitutional Law (2017).

(10) Ganesh Sitaraman & Ingrid Wuerth, The Normalization of Foreign Relations Law, 128 Harv. L. Rev. 1897 (2015).

(11) Pierre-Hugues Verdier & Mila Versteeg, International Law in National Legal Systems: An Empirical Investigation, 109 Am. J. Int’l L. 514 (2015).

(12) Thomas Hobbes, Leviathan 90. On the philosophical foundations and influence of the exclusionary approach in the common law tradition, see generally Thomas Poole, Reason of State: Law, Prerogative and Empire (2015), especially pages 56–60.

(13) John Locke, Two Treatises of Government 147 (orig. 1690) (Peter Laslett ed., 2d ed. 1967).

(14) Id. at 146.

(15) Id. at 147.

(16) Id. at 148.

(17) Albert V. Dicey, Lectures Introductory to the Study of the Law of the Constitution 348 (1885).

(18) Id. at 390.

(19) R (Miller) v. Secretary of State for Exiting the European Union, [2017] UKSC 5, [2018] A.C. 61, [50].

(20) Khadr v. Canada (Prime Minister), 2010 SCC 3, [2010] 1 S.C.R. 44, [34].

(21) Council of Civil Service Unions v. Minister for the Civil Service, [1985] 1 A.C. 374, 418 (HL per Lord Roskill).

(22) Locke, supra note 13, at 145.

(23) The Arantzazu Mendi, [1939] A.C. 256, 264 (HL per Lord Atkin).

(24) W. Harrison Moore, Act of State in English Law 1–2 (1906).

(25) Serdar Mohammed v. Ministry of Defence, [2017] UKSC 1, [2017] A.C. 649.

(26) Oetjen v. Central Leather Co., 246 U.S. 297, 302 (1918). But see Louis Henkin, Foreign Affairs and the United States Constitution 143–148 (2d ed. 1996); Thomas M. Franck, Political Questions/Judicial Answers: Does the Rule of Law Apply to Foreign Affairs? (1992).

(27) Daniele Amoroso, A Fresh Look at the Issue of Non-Justiciability of Defence and Foreign Affairs, 23 Leiden J. Int’l L. 933 (2010); Daniele Amoroso, Judicial Abdication in Foreign Affairs and the Effectiveness of International Law, 14 Chinese J. Int’l L. 99 (2015); Elizabeth Zoller, Droit des Relations Extérieures 298 ff (1992).

(28) Paul Duez, Les Actes du Gouvernement (1935, repr. 2006); Moncef Kdhir, La Théorie de l’Acte de Gouvernement dans la Jurisprudence du Conseil d’Etat relative aux Relations Internationales de la France à l’épreuve du Droit International, 4 J.D.I. 1059 (2003).

(29) Described as “mesures qui peuvent être appréciées indépendamment de leurs origines ou de leurs incidences internationales”: Dalloz, Les Grands Arrêts de la Jurisprudence Administrative 9 (17th ed. 2009).

(30) ce 23 Sept. 1992, Nos. 120,437 and 120,737, GISTI et MRAP (Conseil d’Etat) [1992] A.J.D.A. 752, (1992) 106 I.L.R. 198; ce 29 Sept. 1995 No. 171277, Association Greenpeace France (Conseil d’Etat) [1995] A.J.D.A. 749, (1995) 106 I.L.R. 231.

(31) President of the Council of Ministers v. Marković (Court of Cassation, Decision No. 8157/2002) (2002) 128 I.L.R. 652; held not contrary to art. 6 European Convention on Human Rights: Marković v. Italy (ECtHR (GC), App No. 1398/03, (14 December 2006).

(32) Art. 2 Charter of the United Nations (signed 26 June 1945, entered into force 24 October 1945) 1 U.N.T.S. 16.

(33) Jens D. Ohlin, The Assault on International Law (2015).

(34) Isabel Hull, A Scrap of Paper: Breaking and Making International Law During the Great War (2014).

(35) Daniel Bethlehem, The Secret Life of International Law, 1 C.J.I.C.L. 23, 33 (2012) (Principal Legal Advisor FCO UK, 2006–11).

(36) James Crawford, International Law as a Discipline and a Profession, 106 Am. Soc. Int’l L. Proc. 471, 484 (2012).

(37) James Crawford, International Law in the House of Lords and the High Court of Australia 1996–2008: A Comparison, 28 A.Y.I.L. 1, 6 (2009).

(38) Karen Knop, Foreign Relations Law: Comparison as Invention, ch. 3 in this volume, at p.53.

(39) See, e.g., Jaemin Lee, Incorporation and Implementation of Treaties in South Korea, ch. 13 in this volume; Tadaatsu Mori, The Current Practice of Making and Applying International Agreements in Japan, ch. 11 in this volume.

(40) See, e.g., Gib van Ert, The Domestic Application of International Law in Canada, ch. 28 in this volume.

(41) Verdier & Versteeg, supra note 11, at 532.

(42) William Blackstone, Commentaries on the Laws of England 67 (9th ed. 1783).

(43) Triquet v. Bath (1764) 3 Burr 1478, 97 ER 936 (Lord Mansfield); see Campbell McLachlan, Foreign Relations Law 2.40 ff (2014).

(44) Verdier & Versteeg, supra note 11, at 528.

(45) U.S. Const. art. VI; see Curtis A. Bradley, International Law in the U.S. Legal System ch. 2 (2d ed. 2015).

(46) Restatement of the Law Fourth, The Foreign Relations Law of the United States § 310 (2018). For comparative discussion of the status of treaties in domestic legal systems, see Duncan B. Hollis, Merritt R. Blakeslee, & L. Benjamin Ederington, National Treaty Law and Practice (2005); and Dinah Shelton, International Law in Domestic Legal Systems (2011).

(47) See, e.g., Restatement (Third) of the Foreign Relations Law of the United States (1987); vol. 61 International Relations Law, in Halsbury’s Laws of England (5th ed. 2010).

(48) Andre Nollkaemper, National Courts and the International Rule of Law 53 (2011).

(49) Karen Knop, Here and There: International Law in Domestic Courts, 32 NYU J. Int’l L. & Pol. 501, 516 (2000).

(50) Helmut P. Aust & Georg Nolte, The Interpretation of International Law by Domestic Courts (2016).

(51) Hersch Lauterpacht, The Function of Law in the International Community 397 (1933, rev. ed. 2011).

(52) Art. 4(1) ILC Draft Articles on Responsibility of States for Internationally Wrongful Acts, [2001] 2(2) YB ILC 26.

(53) R v. Lyons, [2002] UKHL 44, [2003] 1 A.C. 976, [105] per Lord Millett.

(54) U.S. Const. art. II, § 2.

(55) The Federalist No. 75 (Madison), in Alexander Hamilton, James Madison, & John Jay, The Federalist Papers (1788, republished 2008).

(56) See, e.g., art. 73(3) of the Japanese Constitution, discussed in Tadaatsu Mori, The Current Practice of Making and Applying International Agreements in Japan, ch. 11 in this volume; arts. 60 and 73 of the Korean Constitution, discussed in Jaemin Lee, Incorporation and Implementation of Treaties in South Korea, ch. 13 in this volume.

(57) Pt. 2 Constitutional Reform and Governance Act 2010 (UK); McLachlan, supra note 43, at 5.37–5.90,

(58) See Katja S. Ziegler, The Use of Military Force by the United Kingdom: The Evolution of Accountability, ch. 43 in this volume; McLachlan, supra note 43, at 4.46–4.83.

(59) Hiromichi Matsuda, International Law in Japanese Courts, ch. 30 in this volume.

(60) Shergill v. Khaira, [2014] UKSC 33, [2015] A.C. 359, [42].

(61) Convention for the Protection of Human Rights and Fundamental Freedoms, 213 U.N.T.S. 221 (signed 4 November 1950, entered into force 3 September 1953).

(62) Francis A. Mann, The Consequences of an International Wrong in International and National Law, 48 Brit. Y.B. Int’l L. 1 (1976), reprinted in Francis A. Mann, Further Studies in International Law 141 (1990).

(63) Roberts, supra note 8, at 105–107.

(64) Franck, supra note 26, ch. 7.

(65) Oona A. Hathaway, A Comparative Foreign Relations Law Agenda: Opportunities and Challenges, ch. 5 in this volume, at p.79.

(66) Martti Koskenniemi, Foreword, in Roberts, supra note 8, at xiv.

(67) James Crawford, International Law as a Discipline and a Profession, 106 Am. Soc. Int’l L. Proc. 471, 484 (2012).

(68) Jens D. Ohlin, The Assault on International Law, ch. 2 (2015).

(69) Knop, supra note 38, at p.60.

(70) See Sir Ernest Satow, A Guide to Diplomatic Practice (1922); John W. Foster, The Practice of Diplomacy as Illustrated in the Foreign Relations of the United States (1906).

(71) Jurisdictional Immunities of the State (Germany v. Italy), [2012] I.C.J. Rep. 99, 123, [56].

(72) Id. at [57].

(73) Al-Adsani v. United Kingdom (App No. 35763/97, 21 November 2001), 34 E.H.R.R. 11, 123 I.L.R. 24, 54 (ECtHR GC).

(74) International Law Commission, Draft Articles on Diplomatic Protection, [2006] 2(2) Y.B. I.L.C. 22.

(75) Diallo (Guinea v. Democratic Republic of the Congo) (Merits), [2010] I.C.J. Rep. 639.

(76) Ulrich Huber, De Conflictu Legum (1686, trans. Ernest Lorenzen in Wigmore, Celebration Legal Essays 199 (Albert Kocourek ed., 1919)).

(77) William S. Dodge, International Comity in Comparative Perspective, ch. 39 in this volume; Lawrence A. Collins, Comity in Modern Private International Law, in Reform and Development of Private International Law: Essays in Honour of Sir Peter North 89 (James Fawcett ed., 2002).

(78) Underhill v. Hernandez, 168 U.S. 250, 252 (1897).

(79) Belhaj v. Straw, [2017] UKSC 3, [2017] A.C. 964. For discussion, see Campbell A. McLachlan, The Foreign Relations Power in the Supreme Court, 134 L.Q.R. 380 (2018).

(80) Moti v. The Queen, [2011] HCA 50, 52, 245 C.L.R. 456 (2011).

(81) Border Guards Prosecution, 100 I.L.R. 364 (BGHst 39, 1) & BVerfGE 95, 98 (1992).

(82) Patrick Kinsch, Le Fait du Prince Étranger 406 (1994).

(83) Campbell A. McLachlan, The Allocative Function of Foreign Relations Law, 82 Brit. Y.B. Int’l L. 349 (2012); Jörg Menzel, Internationales Öffentliches Recht (2011).

(84) For a related argument for the application of conflict of laws techniques to explain the relationship between national law and international law, see Karen Knop, Ralf Michaels, & Annelise Riles, International Law in Domestic Courts: A Conflict of Laws Approach, 103 Am. Soc. Int’l L. Proc. 269 (2010).

(85) Lord Collins et al., Dicey, Morris, & Collins on the Conflict of Laws (15th ed. 2012), Rule 5: “English court have no jurisdiction to entertain an action…for the enforcement…of a penal, revenue or other public law of a foreign State.”

(86) See Menzel, supra note 83; McLachlan, supra note 43, at 5.113–5.190.

(87) Libman v. The Queen, [1985] 2 S.C.R. 178, 208, 84 I.L.R. 672, per La Forest J.

(88) As the Supreme Court of Canada found when it sought to apply such principles to the extraterritorial conduct of Canadian officials in breach of fundamental human rights norms in Khadr v. Canada (No. 1), 2008 SCC 28, [2008] 2 S.C.R. 125. See van Ert, supra note 40; McLachlan, supra note 43, at 8.87–8.90.

(89) Robert Jennings & Arthur Watts (eds.), Oppenheim’s International Law (9th ed. 1992) vol. 1 “Peace” at 457–458; see also Vaughan Lowe & Christopher Staker, Jurisdiction, in International Law 313, 320 (Malcom D. Evans ed., 3d ed. 2010).

(90) Hazel Fox, The Law of State Immunity 2, 751 (2d ed. 2008) (emphasis added).

(91) Francis A. Mann, The Sacrosanctity of the Foreign Act of State, 59 L.Q.R. 42 (1943), reprinted in Francis A. Mann, Studies in International Law (1973), 420, 438; see also Lord Collins et al., Dicey, Morris & Collins on the Conflict of Laws (15th ed. 2012), at 5-047.

(92) R v. Bow Street Metropolitan Stipendiary Magistrate, ex p Pinochet Ugarte (No. 3), [2000] 1 A.C. 147 (HL); cf. Jones v. Ministry of Interior of the Kingdom of Saudi Arabia [2006] UKHL 26, [2007] 1 A.C. 270; Jurisdictional Immunities of the State (Germany v. Italy), [2012] I.C.J. Rep. 99.

(93) Jones v. Saudi Arabia, [49] per Lord Hoffmann.

(94) Pinochet, 198 per Lord Browne-Wilkinson, citing Demjanjuk v. Petrovsky, 603 F. Supp. 1468 (N.D. Ohio 1985); 776 F. 2d 571 (6th Cir. 1985).

(95) Id., 205; Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (CAT), 1465 U.N.T.S. 85, art. 5(2) (signed 10 December 1984, entered into force 26 June 1987).

(96) Id., 141, [95].

(97) Jones v. Saudi Arabia, [25] per Lord Bingham: “article 14 of the Torture Convention does not provide for universal civil jurisdiction.” See also Kazemi Estate v. Islamic Republic of Iran, 2014 SCC 62, [2014] 3 S.C.R. 176, [153]: “the peremptory norm prohibiting torture has not yet created an exception to state immunity from civil liability in cases of torture committed abroad.”

(98) R (Gentle) v. Prime Minister [2008] UKHL 20, [2008] 1 A.C. 136, [24].

(99) R v. Jones (Margaret) [2006] UKHL 16, [2007] 1 A.C. 136, [64].

(100) Id., [30].

(101) [1976] A.C. 249, 282.

(102) Id., 278.

(103) Kuwait Airways Corp v. Iraqi Airways Co. (Nos. 4 & 5), [2002] UKHL 19, [2002] 2 A.C. 883.

(104) Williams & Humbert Ltd. v. W & H Trade Marks (Jersey) Ltd., [1986] 1 A.C. 368.

(105) [2017] UKSC 3, [2017] A.C. 964. See Eirik Bjorge & Cameron Miles, Crown and Foreign Acts of State before British Courts: Rahmatullah, Belhaj, and the Separation of Powers, ch. 40 in this volume; McLachlan, supra note 79.

(106) See Bjorge & Miles, supra note 105.

(107) Id. at pp.730–731.

(108) Belhaj v. Straw, [2017] UKSC 3, [2017] A.C. 964 at [234–240].

(109) For detailed critique, see McLachlan, supra note 79, at 398–400.

(110) Id. at [81–102] (approving Habib v. Commonwealth of Australia, [2010] FCAFC 12, (2010) 265 A.L.R. 50; Moti v. The Queen, [2011] HCA 50, (2011) 245 C.L.R. 456).

(111) Id. at [102].

(112) Buttes Gas v. Hammer (No. 3), [1982] A.C. 888 (HL).

(113) J H Rayner (Mincing Lane) Ltd. v. Department of Trade and Industry, [1990] 2 A.C. 418 (HL).