The Role of Principles and General Principles in the ‘Constitutional Processes’ of International Law

Abstract

The fundamental elements of the international legal system remain subject to debate. Constitutionalism is merely the latest instalment of this continuing conversation on the very nature of international law. In this context certain foundational aspects may be labelled as the system’s ‘constitutional processes’. The primary argument presented in this article is that principles and ‘general principles of law’, two frequently overlooked categories of norms, are particularly useful tools for the enhancement of these constitutional processes. While often conflated, principles and general principles are distinct, performing different roles in the architecture of the international legal system. Renewed attention and debate on the norms beyond treaties and custom is critical for the enhancement of international law’s systemic features. Two broad examples are given in support of this claim. First, general principles of law have the potential to add substance to the notion of an international community and the role of this community in the creation of international norms. Second, the legal framework for the judicial settlement of international disputes can be rendered more robust through the use of principles and general principles of law. While attempting to redesign or reconceptualise the system, constitutionalists have failed to actually engage with the system. Yet, the popularity of the constitutionalism debate presents an opportunity to re-examine the system’s constituent norms and consider their potential to strengthen international law’s constitutional processes.

1 Introduction

At its core, the debate on the constitutionalisation of international law is nothing new. In search of systemic coherence, international lawyers have had recourse to the language and concepts of domestic constitutional law, but the discussion continues to be one on the very nature of the international legal system. Approaching international law from a constitutionalist perspective and seeking to affix constitutional labels to the international system is not per se a problem, yet it does not facilitate significant change. The driving force behind any real change in international law will be a renewed discussion on the actual functions of international law’s systemic elements, in particular the different norms of which the system is composed. There is one category of norms that continues to be overlooked: ‘general principles of law’ as contained in Article 38(1)(c) of the Statute of the International Court of Justice.¹ General principles remain underexplored in comparison to treaties and customary law, with a great variety of meanings and functions ascribed to them. To some they are ‘foundational principles’² of the international legal system as a whole. For others they may exist as ‘soft law’,³ as inchoate custom,⁴ or primarily perform a gap-filling function.⁵ The terminology of general principles perpetuates this lack of clarity, as does the distinct absence of any coherent methodology or explanation of the nature of these norms by international actors.⁶ Given the level of confusion, it is unsurprising that constitutionalist accounts have not fully engaged with general principles. It is the goal of this article to use the momentum of the constitutionalisation debate to reignite the discussion on the nature and function of general principles of law. In turn, it will become clear that there is significant potential for these norms to serve as a tool to advance the goals of constitutionalism and augment international law’s systemic features.

In pursuing this purpose this contribution progresses in three main parts. First, in Sect. 2 there is an exploration of the different facets of the constitutionalisation debate. In ‘taking stock’ of the constitutionalism debate, it is argued that constitutional approaches have not directly facilitated a great deal of change in international law, but are merely the continuation of discussions on the nature of the international legal system. This discussion serves to highlight the dimensions and objectives of constitutionalist accounts, and in doing so demonstrates that the essence of such accounts is the enhancement of international law’s systemic elements and coherence: its ‘constitutional processes’. Second, Sect. 3 revisits ‘general principles of law’ from the perspective of the distinction between rules and principles. This conceptual clarity is essential if there are to be any real shift in the nature of the international legal system and its ‘constitutional processes’. Here it is asserted that the norms embodied in Article 38(1)(c) ICJ Statute are in fact rules, and should be clearly distinguished from principles in the true sense. Third, Sects. 4 and 5 provide examples of the role that principles and general principles can play in the enhancement of the ‘constitutional processes’ of the international legal system. Section 4 deals with the scope for general principles to function as a source of law for the international community. Then, Sect. 5 examines the scope to strengthen the mechanics of the international judicial settlement of disputes on the back of an improved understanding of principles and general principles. This analysis shows that re-examining the issues surrounding these underexplored norms can serve to establish or reinforce key constitutional elements of the modern (and developing) international legal system.

2 The ‘Constitutional Processes’ of the International Legal System

It is first necessary to identify international law’s ‘constitutional processes’ as the object of inquiry. To that end, this section begins with some brief clarifications on the terminology to be employed. It then identifies the different strands of constitutionalist approaches to international law. Finally, it is argued that the various aspects of constitutionalist accounts are, at their core, nothing new. Constitutionalism is a continuation of the debate on the very concept of international law. More specifically it is a discussion on the scope for international law to function as a legal system, and on the nature of this legal system.

2.1 Constitutions, Constitutionalisation, and Constitutionalism

Firstly, the term ‘constitution’ can be understood as the set of principles and procedures used to keep the exercise of political power in check.⁷ A constitution determines the powers of the actors within the system it governs, and regulates the exercise of these powers. Philip Allott has asserted that it is through a constitution that ‘society finds the means to establish itself as a structure and to organise itself as a system’.⁸ A distinction is typically drawn between the formal and material constitution⁹; the formal written document on the one hand, and the broader functional concept on the other.¹⁰ A constitution is more than the formal written text, and a full understanding of a society’s constitutional architecture requires examination of other norms and values, as well as the actual interpretation and application of the formal constitution in practice.¹¹ Secondly, ‘constitutionalisation’ refers to the ‘continuing process of the emergence, creation, and identification of constitution-like elements in the international legal order’.¹² Finally, the term ‘constitutionalism’ refers to the intellectual movement that seeks to examine the constitutionalisation of international law¹³; it is an ‘academic artefact’¹⁴ and has developed into its own interdisciplinary research field.¹⁵

2.2 The Dimensions of International Constitutionalism

Constitutionalist accounts of international law take many forms.¹⁶ It has been noted that there are four main aspects or dimensions of constitutionalism.¹⁷ The first can be identified as social constitutionalism, which views the aim of constitutionalisation as the protection and regulation of the various social interactions between international actors. Advocates of social constitutionalism place great emphasis on the participation of the individual in the international legal order,¹⁸ and the protection of individual rights.¹⁹ Secondly, institutional constitutionalism argues for the placing of limitations on the power in institutions, both global and domestic.²⁰ Jan Klabbers has remarked that constitutionalism concerns the regulation of the activities of international organisations,²¹ and Anne Peters has explored the potential constitutional framework offered by specific international organisations.²² Within this dimension of constitutionalism it has been argued that the domestic constitutions of states no longer form complete legal orders, and that any constitutionalisation of international law is accompanied by a ‘deconstitutionalisation’ of domestic orders.²³ Thirdly, normative constitutionalism is focused on the development of or enhanced role for hierarchically superior norms.²⁴ Erika de Wet has argued that there exists an international value system of norms with ‘strong ethical underpinnings’ such as human rights rules, and has attached particular significance to jus cogens norms and the concept of obligations erga omnes.²⁵ Similarly, for Tomuschat there exists a core of norms that apply beyond the will of states.²⁶ Such accounts are linked to claims of the apparent decline of the Westphalian world order exclusively based on the consent of and regulating interactions between sovereign states.²⁷ In its place, the argument goes, is a system in which the individual has more rights and obligations,²⁸ and where the raison d’être of the international order is the protection of the interests of humanity and human dignity²⁹ as opposed to the preservation of state sovereignty.³⁰ Finally, analogical constitutionalism is concerned with the transposition of domestic constitutional law structures to the international plane.³¹ A prominent example is Bardo Fassbender’s claim that the UN Charter³² functions as the written and formal constitution of the international community.³³ There have been similar attempts to draw analogies between the constitutional framework of the European Union (EU) and international law,³⁴ as the EU’s system may be regarded as the most advanced model of a constitutional order beyond the state.³⁵

2.3 ‘Constitutional Processes’: Old Wine in New Bottles?

As Jean d’Aspremont has remarked, these debates on the constitutionalisation of international law are merely the continuation of a more fundamental discussion on the nature and concept of international law.³⁶ In the Concept of Law, Herbert Hart categorised international law as a simple form of social structure consisting of solely primary rules and therefore not meeting the conditions to be classified as a legal system.³⁷ Each of the abovementioned aspects of constitutionalism, albeit in different ways, attempts to refute Hart’s claim; constitutionalism seeks to develop or reformulate the basic structures and identity of international law as a legal system. An international legal system, like any legal system, will be comprised of certain principles and values on the one hand, and legal structures that function in the furtherance of these values on the other. In a similar sense, de Wet has argued that the international constitutional order is comprised of an international community, together with an international value system and structures for its enforcement.³⁸ Others have noted certain fundamental norms and organising principles that form the basis of the system.³⁹ From the discussion above, there are recurring issues that can be said to form the ‘constitutional processes’ of the international legal system; fundamental systemic elements that dictate the overall nature and direction of the system, as well as setting out basic rules that govern its operation. The identity and role of the system’s participants, the creation of legal rules, and the nature of enforcement mechanisms are examples of such processes.

3 Rules and Principles in the International Legal System

If international law’s constitutional processes are to be identified, developed, and refined, there must be clarity as to the nature and functions of the system’s norms. Put differently, international lawyers cannot facilitate a shift in the foundations of the international legal system unless these foundations have been accurately identified and engaged with. The distinction between rules and principles is central to understanding these normative foundations. The elaboration of a distinction between rules and principles in a legal system has been a central conceptual apparatus for many legal theorists.⁴⁰ This section will revisit the distinction between rules and principles in international law, and in doing so asserts three main claims: (1) there is a logical conceptual distinction between these two categories of norms; (2) this distinction has been adopted in the international legal system; and (3) ‘general principles of law’ in the sense of Article 38(1)(c) ICJ Statute were designed to be and in fact function as rules.

3.1 The Fundamental Distinction between Rules and Principles

Legal systems are composed of a number of different norms. While the scope of the term ‘norm’ may vary depending on its context, it may be generally defined as ‘a standard of performance, a measurement scale […] used to predict […] and diagnose performance contrary to expectations’.⁴¹ It may be the case that in legal contexts the term norm is equated to the term ‘rule’,⁴² but for present purposes the term norm is used in a broader sense in line with the definition above, and so includes (at least) rules and principles. These two types of norms are of a fundamentally different nature, as are the functions they perform. Firstly, there is a significant difference in the formation of rules and principles, and the consequence of conflict. The existence of a rule is grounded in the fulfilment of criteria set out in other rules.⁴³ That is to say, rules are either valid or not; only when the formal procedural conditions for its creation are met does a rule come into existence as part of the system.⁴⁴ Conversely, it is not important that principles are enacted through certain procedures and subject to certain conditions, instead it is a dimension of weight that is characteristic of principles.⁴⁵ Robert Alexy has spoken of the ‘construction’ of principles from certain constitutional rights and on the basis of a proportionality assessment.⁴⁶ This fundamental difference becomes more apparent in situations of conflict. When rules collide, either one is deemed invalid or a valid exception is created.⁴⁷ In situations where principles are in conflict, the competing principles are balanced against one another. An overridden principle is not deemed to be invalid, and may itself prevail in a different situation.⁴⁸ In other words, conflicts of rules are solved in the validity domain, whilst competition between principles is resolved on the basis of their value in a given situation.⁴⁹

Secondly, rules and principles are structurally different. Rules are composed of conditions, upon the fulfilment of which a legal consequence follows. Ronald Dworkin remarked that rules apply in an ‘all or nothing fashion’⁵⁰; either the conditions of the rule are satisfied, and the consequence takes effect, or they are not and the rule contributes nothing to the situation. It is this feature that led Alexy to label rules as ‘definitive commands’, and thus distinguishing them from principles as ‘optimisation commands’.⁵¹ Principles, then, do not provide necessary and sufficient reasons for a consequence to follow in the same way as rules, instead providing prima facie arguments, or ‘first-order reasons’⁵² for reaching a certain conclusion.⁵³ As such, they are ‘should’ statements that require a goal to be ‘realised to the greatest extent possible in the circumstances’.⁵⁴

Finally, there are clear functional differences between rules and principles. The various functions of rules can be seen in the well-known distinction between primary and secondary rules.⁵⁵ Primary rules impose duties, grant rights, or create legal or institutional facts.⁵⁶ Secondary rules are ‘rules about rules’⁵⁷; they govern the creation, modification, and extinction of other rules, as well as determining (the consequences of) their violation.⁵⁸ Principles, on the other hand, have two related functions within a legal system. First, they act as the impetus for the creation of rules. Put differently, rules can be enacted to further the values or objectives embodied in principles.⁵⁹ Second, principles are crucial in the process of legal reasoning. As aptly stated by Sir Gerald Fitzmaurice, ‘[a] rule answers the question “what”: a principle […] the question “why”’.⁶⁰ As such, the reasons espoused by principles can assisting in the interpretation and application of rules to a given problem.⁶¹

3.2 International Law’s Acceptance of this Distinction

In international law, the ICJ seems to approach the task of labelling the norms it uses with some degree of levity. In Gulf of Maine,⁶² the Court stated that ‘the association of the terms “rules” and “principles” is no more than the dual expression to convey one and the same idea’.⁶³ Similarly, in Gabčíkovo-Nagymaros reference was made to the ‘concept of sustainable development’, with no further explanation given as to the nature of this norm.⁶⁴ Notwithstanding this terminological ambiguity, the existence and functioning of the distinction is apparent in the reasoning of international courts and tribunals. In Kupreškić, the Trial Chamber of the International Criminal Tribunal for the former Yugoslavia (ICTY) held that Articles 57 and 58 of the First Additional Protocol to the Geneva Conventions⁶⁵ were to be interpreted narrowly in light of the ‘principle of humanity’ and ‘dictates of public conscience’.⁶⁶ In Border and Transborder Armed Actions,⁶⁷ the ICJ referred to Nuclear Tests in reaffirming that the principle of good faith was ‘one of the basic principles governing the creation and performance of legal obligations’.⁶⁸ Yet, it was held that this principle is ‘not in itself a source of obligation where none would otherwise exist’.⁶⁹ The recent decision in Immunities and Criminal Proceedings⁷⁰ more explicitly confirms the existence of a distinction between rules and principles in international law, as well as the relationship between these two categories. In upholding France’s preliminary objection, the Court held that Article 4 of the Palermo Convention’s reference to ‘the principles of sovereign equality’ does not include the obligations conferred by the customary rules of state immunity.⁷¹ This conclusion was reached despite the acknowledgment that ‘the rules of State immunity derive from the principle of sovereign equality of States’.⁷²

Revisiting and embracing this distinction between rules and principles will significantly contribute to the debate on international law’s constitutional processes. This distinction centres on the very nature and functions of a legal system’s constituent norms, and their interactions with one another. In both international law general, and the constitutionalism debate specifically, there is frequently a failure to rigorously assess the nature of the norms in question. This is particularly the case with general principles of law, which despite their name function as international legal rules.

3.3 General Principles of Law as Rules

To speak of a source of law is to speak of the criteria and processes for the ascertainment of legal rules,⁷³ and it is rules that are constitutive of legal systems.⁷⁴ That Article 38(1)(c) ICJ Statute is one of the established sources of international law is uncontroversial.⁷⁵ In the deliberations of the Advisory Committee of the Permanent Court of International Justice (PCIJ), it was clear that the rationale for the introduction of general principles of law was to preclude situations of non liquet,⁷⁶ that is, to avoid a situation in which there was no applicable legal rule to a given dispute. Subsequently, it has become clear that the invocation and application of norms under the moniker or in the spirit of ‘general principles of law’ has frequently been the invocation and application of rules.

On occasion, the invocation or application of a ‘general principle of law’ has been the invocation or application of a primary rule. For example, in its first contentious case, Corfu Channel, the Court found that the United Kingdom (UK) was unable to rely on the 1907 Hague Convention XIII⁷⁷ as it was applicable only in times of war. Instead, it upheld the UK’s claim on the basis of a number of ‘general and well-recognized principles’: ‘elementary considerations of humanity […] the principle of freedom of maritime communication; and every State’s obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States’.⁷⁸ Consequently, the Court found a number of obligations incumbent upon and violated by Albania as a result of its placing of mines in its waters. Similarly, in Right of Passage Portugal asserted that its right to pass through Indian territory (a primary rule) was rooted in general principles of law, ‘which have their own binding force’.⁷⁹ Further, in Difference Relating to Immunity from Legal Process of a Special Rapporteur of the Commission of Human Rights the Court referred to a ‘generally recognized principle of procedural law’ in finding that a Malaysian court had violated its obligation to rule on issues of immunity in limine litis.⁸⁰

More frequently, however, general principles of law are secondary rules. In Avena and Other Mexican Nationals,⁸¹ Mexico argued for existence of a rule that excludes the evidence that is obtained in violation of due process, asserting that the ‘exclusionary rule is a general principle of law under Article 38(1)(c) [of the ICJ Statute]’.⁸² Further, in LaGrand⁸³ the Court found that provisional measures enacted under Article 41 of the ICJ Statute were binding on the basis of a ‘principle’ recognised by the PCIJ⁸⁴ that ‘parties to a case must abstain from any measure capable of exercising a prejudicial effect in regard to the execution of the decision to be given’.⁸⁵ Moreover, in Klöckner v. Cameroon the original award was annulled due to the failure of the tribunal to provide sufficient evidence for the existence of a general principle.⁸⁶ Finally, in Effect of Awards it was concluded that there existed ‘a well-established and generally recognized principle of law, [that] a judgment rendered by […] a judicial body is res judicata’.⁸⁷ The status of res judicata as a general principle of law within the meaning of Article 38(1)(c) ICJ Statute is undisputed.⁸⁸

General principles have an inherent gap-filling function, most commonly deployed to identify basic procedural rules where treaties and custom fail to provide answers. Both manner in which this is done and the resulting rules can contribute to the main goals of global constitutionalism. Each of the following sections examines the scope for principles and general principles to establish or enhance some of the constitutional processes of the international legal system.

4 General Principles as the Law of the ‘International Community’

The mode of creation of general principles of law is one of the issues where the lack of clarity in comparison with treaties and customary rules becomes very clear. For treaties, the rules of the Vienna Convention on the Law of Treaties⁸⁹ set out the formal procedures for signature and ratification,⁹⁰ and provide for certain conditions of validity.⁹¹ For the ascertainment of customary rules, the ICJ has built a body of case law stating and clarifying the well-known elements of state practice and opinio juris.⁹² There is as yet no such guidance for the ascertainment of general principles of law. Seeking to establish the criteria for the ascertainment of general principles can contribute the establishment of constitutional features in at least two ways. First, there is scope to rely on the concept of the ‘international community’ as a basis for the recognition of general principles. Increased clarity as to international law-making processes enhances its systemic coherence. Second, greater reliance on this source could allow for the creation of rules that are not exclusively dependent on the consent of states, and so seek to serve the interests of the community as opposed to solely those of states.

4.1 Identifying the ‘International Community’

Article 38(1)(c) ICJ Statute provides little assistance on the issue of the ascertainment of general principles. The text itself refers to such norms being ‘recognized by civilized nations’, and it is clear that such terminology is no longer relevant and appropriate, if it ever was.⁹³ In an attempt to modernise this provision and establish clear conditions for the creation of general principles it is suggested that this requirement be revisited, and that doing so will contribute to the constitutionalisation debate.

In the PCIJ Advisory Committee, it was suggested that general principles were to be drawn from rules identified ‘in foro domestico’.⁹⁴ Similarly, some have argued that while the state practice required for custom is that among states, evidence for general principles is to be found within states.⁹⁵ Although recourse to domestic approaches certainly forms part of the determination of general principles, this cannot be the end of the story. As described by Lord McNair in South West Africa, such rules of domestic rules are not transposed ‘“lock, stock and barrel”, ready-made and fully equipped’ into international law.⁹⁶ Therefore, instead of the mechanical transposition of a domestic rule into international law, it is necessary to establish whether there is acceptance of an international rule.⁹⁷ Such an approach would seem to be in line with the conception of general principle used in Article 21(1)(c) of the Rome Statute, which permits the use of domestic rules provided that they are ‘not inconsistent […] with international law’.⁹⁸

To say that general principles of law must be accepted by the ‘international community’ meets the requirement of identifying an international rule. Yet, the question remains as to the precise nature and content of the ‘international community’. At present there is a distinct lack of clarity and coherence as to its substance.⁹⁹ Gleider Hernández has remarked that the invocation of the ‘international community’ is merely a ‘rhetorical technique’¹⁰⁰ and that its use by the ICJ has been ‘purely ornamental’.¹⁰¹ In order to add some precision to the meaning of the term ‘international community’ there are two related issues to be addressed: its membership and its underlying values or interests. It may be that the international community remains exclusively composed of states,¹⁰² but such a conception would seem to be at odds with the current state of the international society. It remains possible to conceive of states as the primary actors in the international legal system,¹⁰³ while also acknowledging that the participants in international society and the values and interests taken into account by international law are broader than the nation-state. For ‘recognition by the international community’ two steps are to be followed. First, a common legal approach to an issue is identified on the basis of a comparative analysis of domestic systems. Second, there is an examination of evidence for an international manifestation of the rule. This could be done by taking into account the views or interests of certain actors, such as certain international organisations or non-governmental organisations,¹⁰⁴ and by examining the compatibility of a particular rule with the underlying principles of the international legal system. This approach grants non-state actors a greater role in the law-making process, both in terms of a consideration of their views as evidence for rule-creation and the prominent role assigned to (international) courts and tribunals in the actual determination of general principles. Reliance on recognition of the international community as the basis for the creation of general principles has potential implications beyond this context. The explicit recognition of a non-state actor participation in this framework could contribute towards eroding the distinction between ‘subjects’ and ‘objects’ in international law,¹⁰⁵ and towards an alternative understanding of participants.

Further, recognition of and by the international community implies the recognition of values and interests that go beyond the individual interests of states that are safeguarded by bilateral legal relationships. As Sir Hersch Lauterpacht put it, the will of international society (the voluntas civitatis maximae) could become the driving force for law-creation in international law.¹⁰⁶ There are certain values and objectives that underpin the international legal system, such as the maintenance of international peace and security, and the protection of fundamental rights.¹⁰⁷ Such values are not in and of themselves international legal norms, but can be embodied in principles such as sovereignty¹⁰⁸ and humanity.¹⁰⁹ As discussed above, these principles in turn influence the creation and application of legal rules, including general principles. The determination of general principles requires the ascertainment of an international rule, and the underlying values and principles of the international community could play a key role in this regard. That is to say, a prospective general principle is more likely to be deemed to be recognised by the international community if it is consistent with (or indeed furthers) the underlying principles and values of the system. There is of course much work to be done here; the membership of the international community and its underlying values may be in a relationship of mutual influence, and may evolve over time. As such, their role in international law-making may also develop. Yet, a first crucial step would be to recognise that such a community exists and that it has clear potential to play a role in the constitutional processes of international law.

4.2 A Source of Community Rules?

A related issue is whether this conception of general principles as based on recognition of the international community can lead to the proliferation of rules that are not directly predicated on the consent of states; the public elements of public international law.¹¹⁰ In this regard it is common to discuss the concept of jus cogens norms as a mechanism for the imposition of public law or community values on states.¹¹¹ The scope for general principles to serve as a source of rules with the character of jus cogens was explored in the most recent ILC report on the topic.¹¹² Despite some debate,¹¹³ it was widely acknowledged that general principles could achieve this status.¹¹⁴ Such a conclusion was based on the determination that reference to ‘general international law’ in Article 53 VCLT¹¹⁵ includes general principles in the sense of Article 38(1)(c) ICJ Statute.¹¹⁶ However, it seems unlikely that general principles will make much of a contribution here. The requirement of state acceptance of the peremptory character of a norm in Article 53 VCLT suggests that it is customary law that will serve as the driving force behind any enhanced role for jus cogens.¹¹⁷

Nevertheless, there may still be scope for principles and general principles to contribute to the development of a public dimension of international law. First, Simma and Alston famously explored the potential of general principles to function as a source of human rights rules,¹¹⁸ and the same could be true for rules of international humanitarian law. The ICJ’s reference to ‘fundamental principles’ of human rights in Tehran Hostages,¹¹⁹ and ‘general principles of humanitarian law’ in Nicaragua¹²⁰ seems to suggest an openness to such an approach.¹²¹ Second, a more pronounced role for principles may lead to an increased role for the invocation of responsibility for violations of obligations erga omnes. In Barcelona Traction the Court held that there are certain obligations owed by a state ‘to the international community as a whole’ and that ‘in view of the importance of the rights involved, all states have an interest in their protection’.¹²² This concept of obligations erga omnes as a mechanism for the enforcement of certain substantively important obligations later became part of ILC’s Articles on the Responsibility of States for Internationally Wrongful Acts (ARSIWA).¹²³ Despite the existence of this mechanism, there is no consensus as to which obligations have this erga omnes character. After explaining the nature of the concept in Barcelona Traction the ICJ did shed some light on this by listing prohibitions of aggression, genocide, slavery, and racial discrimination as examples of such obligations.¹²⁴ Some further clarity came in the East Timor case,¹²⁵ as well as the advisory opinions on the Wall¹²⁶ and Chagos,¹²⁷ where the Court identified certain erga omnes obligations related to self-determination.¹²⁸ Further, there have been numerous academic attempts to broaden this category of obligations into other areas, such as human rights, the protection of the environment, and development law.¹²⁹ Principles, as embodying the underlying values and interests of the international community, could play a role in identifying those obligations that are substantively important enough to generate erga omnes standing.

5 Strengthening International Judicial Settlement of Disputes

A greater role for principles and general principles could also give rise to more robust and effective mechanisms of international dispute settlement. It has been claimed that no community can exist ‘without being able to discern an all-embracing judicial function safeguarding an even operation of the law within such community’.¹³⁰ The lack of compulsory judicial settlement of disputes in international law is well-documented,¹³¹ and there are indeed situations in which the weaknesses of the international judicial system are exposed. Principles and general principles could serve to strengthen this system in two main respects: (1) clarifying the international judicial function and improving quality of legal reasoning, and (2) enhancing the procedural framework governing international judicial proceedings.

5.1 The International Judicial Function and Legal Reasoning

An oft-cited function of general principles is the filling of legal gaps where treaties and custom have no answers.¹³² Embracing this function requires not only the abovementioned clarity on the identification of general principles, but reconsideration of the possibility and scope of judicial law-making. Lauterpacht asserted that the completeness of international law is an a priori principle of the international legal system,¹³³ and that the international judiciary has a role in filling any gaps in the law with recourse to, inter alia, general principles of law.¹³⁴ This principle of completeness, together with more inclusive participation and the erosion of the absolute dominance of state sovereignty, could lead to a greater role for the judiciary in a true international legal system. Yet, central to the success of this proposition is a more reasoned and transparent approach to the determination of general principles, as well as customary rules.¹³⁵ The international community recognition approach to the ascertainment of general principles is, in essence, an argumentative process; what Martti Koskenniemi has labelled the ‘constructivist thinking of legal argumentation’.¹³⁶ This requires ‘constructive activity from the judge who must provide a set of arguments in light of which the decision seems coherent with [international law’s] goals and values’.¹³⁷ Charles Kotuby and Luke Sobota have labelled this the ‘Darwinian’¹³⁸ aspect of the formation of general principles; depending on the strength of reasoning employed and evidence for their existence, some of these rules will ‘shine as bright beacons’ while others ‘will flicker and die near instant deaths’.¹³⁹

The principle of effectiveness may also serve as a tool for achieving a more robust international judicial function. Salvatore Zappalà has claimed that this principle has served as ‘a cornerstone of international law’,¹⁴⁰ and it seems to have some support in the case law of the ICJ. In one of the Fisheries Jurisdiction cases the Court was faced with a question on the interpretation of a reservation to a treaty; it held that in such cases the interpretation that gives effect to the object and purpose of the reservation is to be adopted.¹⁴¹ Recourse to the principle of effectiveness has been made in the recent discussion on the immunity of heads of state before the International Criminal Court (ICC). Dapo Akande and Talita de Souza Dias have argued that Article 27(2) Rome Statute would be deprived of its effectiveness if the immunity of heads of state precluded their arrest by other states pursuant to an arrest warrant.¹⁴² It seems that such an argument is consistent with the interpretation of the ICC itself in its decision on South Africa’s failure to arrest Omar Al-Bashir, where it was held that the object and purpose of Article 27 Rome Statute would be ‘reduced to a purely theoretical concept’ if immunities remained intact in such situations.¹⁴³

5.2 Enhancing International Procedural Law

It is clear that many of the candidates for ‘general principles of law’ are secondary rules of adjudication or enforcement; what may be understood as procedural rules. This becomes clear upon an examination of Cheng’s ‘Draft Code of General Principles’ annexed to his seminal work on the topic.¹⁴⁴ Indeed, of the sixteen norms listed only Article 1’s reference to ‘good faith’ is not clearly a procedural rule of adjudication or enforcement. The main reason for the prominence of general principles’ (potential) role in this area is the frequent absence of applicable treaties or customary rules. International courts and tribunals have regularly had to determine for themselves certain rules governing the conduct of proceedings before them. For example, in Tadić the ICTY found that there exists a ‘well-known principle of Kompetenz-Kompetenz’ that formed part of a court’s ‘incidental or inherent jurisdiction’.¹⁴⁵ The situation is similar in relation to rules on evidence, with the ICJ considering the admission of evidence in several cases. In Corfu Channel, it was held that the characteristics of interstate litigation as between two sovereign entities allowed for the admission of circumstantial evidence.¹⁴⁶ Similarly, in Nicaragua the Court found that it has broad discretion to decide on the admission of evidence subject to ‘general principles of judicial procedure [that] necessarily govern the determination of what can be regarded as proved’.¹⁴⁷ The issue of lawyer-client privilege is another procedural matter that has been addressed by international courts and tribunals. In Bangura et al., the Special Court for Sierra Leone found the existence of a general principle that communications between a lawyer and client are covered by privilege, with the exception where the communication concerns criminal or fraudulent conduct.¹⁴⁸

Despite this tendency, there remain gaps in how courts and tribunals deal with such questions. The ICJ’s reference to ‘general principles of judicial procedure’ in Nicaragua was not followed by any explanation of what these principles actually are. There are also issues arising as to the precise contours of such rules. For example, in Questions Relating to the Seizure and Detention of Certain Documents and Data¹⁴⁹ Timor-Leste asserted that legal professional privilege was a general principle of law, and argued that Australia’s seizure of documents and data violated this rule.¹⁵⁰ In response, Australia asserted that even if such a general principle existed its scope on the international plane was to be construed narrowly so as to not cover all types of communication, and that there existed certain exceptions to this general rule.¹⁵¹ The Court did not address this question directly, and instead relied on the ‘principle of sovereign equality’ to conclude that there was a ‘plausible right to protection’ of the documents in question.¹⁵² Such examples demonstrate an acceptance of the role of courts in identifying rules beyond treaties and custom, yet there is still a need for clarity on how exactly such rules are identified and may develop over time.

6 Concluding Remarks

Constitutionalism is the latest instalment in a continuing conversation on the nature of international law. In seeking to portray or develop a more sophisticated and coherent international legal system, constitutionalists have attempted to attach familiar labels to the system’s fundamental processes. Yet, such labelling has done little to facilitate a shift in the way international law is viewed and functions. A major reason for this is that the nature and functioning of international law’s basic elements remain underexplored. This holds particularly true for two categories of norms: principles and general principles. Overlooking or conflating the system’s normative foundations has limited the extent to which global constitutionalism has precipitated real change in international law. Put differently, while attempting to redesign or reconceptualise the system, constitutionalist have failed to actually engage with the system. However, the popularity of the constitutionalism debate presents an opportunity to re-examine these norms and consider their potential to strengthen the system’s ‘constitutional processes’. Substantiating the concept of the ‘international community’, and bolstering the legal framework for the judicial settlement of disputes are two examples of this potential. These developments would more accurately account for the range and nature of international actors, and the ability of international law to meet contemporary challenges as a true legal system. It is hoped that the continued momentum of international constitutionalism would allow for further discussion on the nature of the international legal system’s basic elements and opportunities for the use of principles and general principles as tools for its advancement.