The Traditional International Legal System

The traditional (or current) international legal system is very much premised upon states and state sovereignty dating back to the Peace of Westphalia in 1648. ^{Footnote 2} The main actors in the international system are states — they are the creators of the law, and it is to them the law applies. Therefore, “international law is primarily a law for the international conduct of states, and not their citizens … [and] the subjects of the rights and duties arising from international law are states solely and exclusively.” ^{Footnote 3} It is relevant to note that this state-based, or territory-based, international system since Westphalia was preceded by a variety of different forms of social and political organization, which included nomadic Mongol tribes who laid claim to the cycle of migration of their livestock, overlapping power structures of feudal lords and monarchies in early medieval Europe, followed by consolidated monarchies, city-states, principalities, city-leagues, and so on. ^{Footnote 4} As such, the so-called “traditional” international system is a relatively new invention with nothing preventing its continuing evolution.

The list of subjects of international law has developed somewhat to include international actors and even individuals. In the 1949 case of Reparation for Injuries Suffered in the Service of the United Nations, the International Court of Justice (ICJ) stated that “throughout its history the development of international law has been influenced by the requirements of international law” ^{Footnote 5} and that “the subjects of law in any legal system are not necessarily identical in their nature or in the extent of their rights, and their nature depends upon the needs of the community.” ^{Footnote 6} These pronouncements by the ICJ came as it recognized the United Nations (UN), an international organization, as a subject of international law with rights and duties, including the right to bring claims under international law. Meanwhile, the rise of international human rights law has created rights for individuals. ^{Footnote 7} Individuals have also been held accountable for war crimes and crimes against humanity, first at the Nuremberg trials and subsequently at international criminal tribunals, special courts, and the International Criminal Court.

In spite of these relatively minor qualifications, international law remains state centred. While the scope of subjects of international law has been broadened ever so slightly, “[t]he principle that only states can generate international law through their customary practices and the conclusion of treaties is maintained.” ^{Footnote 8} As such, “states remain in ultimate control over the formal content of international law.” ^{Footnote 9} Even though limited rights and duties have been recognized for international organizations, like the UN, and individuals, the international system has “never been so compromised as to equate the corporation with the state that gives it existence or to trigger state-like obligations.” ^{Footnote 10} As Peter Muchlinski unequivocally states, “[c]orporations are not subjects of international law.” ^{Footnote 11} Furthermore, “it is states, and not private actors, who have the primary responsibility to regulate corporate conduct.” ^{Footnote 12} However, even under the traditional international legal system, there is potential for corporations to accrue an enhanced, but limited, form of subjecthood. As Jennifer Zerk astutely points out, since states are the makers of international law, “it is open to states to allocate certain international law responsibilities directly to companies, whether as a matter of custom or by treaty.” ^{Footnote 13}

While the issue of legal personality is not at the forefront of this article, it is nonetheless worthy of brief discussion. Many theories of legal personality (global legal pluralism, policy-oriented, transnational law, and so on) focus on non-state actors generally. ^{Footnote 14} This is problematic because it fails to appreciate the extensive differences among disparate non-state actors. While the legitimation accorded through limited legal personality might be highly problematic in the realm of non-state armed groups such as rebels and guerrillas, I would suggest that it is less problematic in the context of the corporations discussed in this article. As noted below, many of the world’s corporations surpass states in terms of power and resources, and their operations have direct consequences for the human and environmental rights of individuals and communities. Such rights are at the heart of CSR and the foundation of the corporate customary international law proposed in this article. This article situates itself in the existing state-centrism of the international system and looks to states to facilitate, or even authorize, the recognition of a phenomenon (corporate customary international law), which may already be in existence. However, this should not be interpreted as negating the potential that international law and the legal personality of corporations could evolve in a different manner.

The Rise of Globalization

The rise of globalization has placed pressure on the traditional international legal system. The traditional roles of actors, such as states and corporations, have evolved such that “[t]he provision of public goods is no longer the preserve solely of governments, and private actors, such as NGOs and multinationals, are involved in global governance processes.” ^{Footnote 15} The boundaries between the private and public spheres of law have been blurred, requiring a reconsideration of the axioms of international law. As Jean-Philippe Robé notes, “[t]he transnationalization of society is challenging the sovereignty of the state; it is challenging the self-ascertained monopoly that state sovereignty claims for itself in the production of norms, and even states’ mere capacity to produce effective norms.” ^{Footnote 16} Christiana Ochoa also remarks on this traditional narrative of state sovereignty and monopoly over international legal personality and law creation, finding that it “is now inaccurate on every count.” ^{Footnote 17}

A primary source of this challenge and the catalyst of these changes has come from the “exponential growth of transnational corporate activity.” ^{Footnote 18} In this era of globalization, “[t]he scope of commercial operations is geographically broader than any previous empire.” ^{Footnote 19} Furthermore, “[o]f the 100 largest economies in the world, 51 are corporations while only 49 are States.” ^{Footnote 20} Corporations therefore possess extensive economic power and, consequently, significant political influence. The transnational scope and vast scale of corporate operations means that corporate activities have both direct and indirect effects of varying degrees of seriousness when it comes to the environment and social issues. ^{Footnote 21} This has prompted increasing calls for, and movements towards, greater public accountability for corporations and even direct obligations for them under international law. ^{Footnote 22}

A Review of the Literature

The traditional conceptions of international law have been challenged by the vast expansion of corporate activity transnationally. This has been acknowledged and discussed by numerous scholars. ^{Footnote 23} Scholars have also attempted to re-evaluate international law formation in light of the extensive power and influence exercised by corporations and other non-state actors, such as individuals and NGOs, within the international system. An examination of the approaches focusing on customary international law as a means of resolving the tension between the traditional international system and the new realities faced in the contemporary international system shows a wide spectrum of suggestions, from quite conservative to more extensive, pushing on the boundaries of the conception of customary international law.

CSR: The Basics

CSR is not subject to one universally accepted definition. ^{Footnote 52} At its most basic, and vague, level, its name indicates that it addresses the responsibility of corporations with respect to society. Of course, “[t]he notion of what is socially responsible is situated by contemporary needs and concerns and thus cannot be pinned down in precise and unchanging terms.” ^{Footnote 53} This perception, however, does not devalue its use as a legal concept since many legal concepts often “remain necessarily undefined in order to foster evolution and development,” such as the concept of the “best interests of the child” or “corporate governance.” ^{Footnote 54} Nonetheless, at its core, CSR recognizes “the need for corporations to take cognizance of persistent global problems,” upon which corporate activities can and have had both direct and indirect affect. ^{Footnote 55}

CSR is composed of a combination of national laws and regulations imposed on corporations by states with regard to environmental protection, health and safety, and consumer protection as well as codes of conduct and other instruments initiated by individual corporations, industries, and international organizations. ^{Footnote 56} As such, CSR and law are, from the outset, very much intertwined. ^{Footnote 57} Nonetheless, CSR is often described as “beyond-law obligations [to] which companies must adhere.” ^{Footnote 58} The phrase “beyond-law obligations” also lends itself to confusion because it pairs the term “beyond law,” which suggests something that is not mandatory, with the word “obligation,” which denotes a binding duty or commitment.

Although many CSR instruments are often described as “voluntary codes of conduct” and the like, many scholars contest the idea that CSR is truly voluntary. ^{Footnote 59} As Kerr, Janda, and Pitts note, “definitions [often] speak of CSR as a ‘business commitment.’ This suggests that CSR has an obligatory force that once undertaken, cannot simply be curtailed or abandoned.” ^{Footnote 60} This is closely linked to the idea of a “social licence to operate” that has been identified by many scholars as being at the core of CSR. ^{Footnote 61} This refers to idea of a reciprocal undertaking between corporations and society, wherein “[i]n exchange for public trust and the social licence to operate its business, the corporation makes a series of social business commitments.” ^{Footnote 62} Consequently, while it appears that there are definite binding obligations to be found in CSR, and though the “norms and the frameworks they compose share many of the same systemic and structural characteristics of State-based positive law,” ^{Footnote 63} ultimately, “[they] do not derive from the legal authority of the State,” and therein seems to lie the difficulty in fully understanding the role and function of CSR in international law. ^{Footnote 64}

Customary International Law: The Basics

The creation of legally binding law through the process of customary international law formation is as old as the international community of states itself. ^{Footnote 65} Whereas the formation of international law through treaties involves the written agreement of states to laws binding between them, customary international law binds all states through practice and “tacit agreement.” ^{Footnote 66} One of the clearest, and, therefore, most often quoted, articulations of the elements of customary international law is found in North Sea Continental Shelf (Federal Republic of Germany v Denmark; Federal Republic of Germany v Netherlands), wherein the International Court of Justice (ICJ) stated:

This passage identifies the two key elements of customary international law: state practice and opinio juris — that is, the belief by states that this practice is obligatory in nature. In the same case, the ICJ further explored the subject of opinio juris, holding that,

These statements serve to emphasize that opinio juris plays an important role in the formation and identification of rules of customary international law.

In their 2000 report, the ILA’s Committee on Formation of Customary (General) International Law provided the following working definition of customary international law:

There are several key features of the ILA report’s working definition that need to be further discussed. Most notably, this reference does not include an express reference to the opinio juris element. The ILA explains that its definition includes “an indirect allusion to this in the words ‘in circumstances which give rise to a legitimate expectation of similar conduct in the future’.” ^{Footnote 70} The report further expresses the belief that “it is usually not necessary to demonstrate the existence of the subjective element before a customary rule can be said to have come into being.” ^{Footnote 71} Instead, “in the context of the formation of general customary law … the main function of the subjective element is to indicate what practice counts (or, more precisely, does not count) towards the formation of a customary rule.” ^{Footnote 72}

The need to distinguish between practice that forms a legal obligation and that which does not is expressed by many other scholars. ^{Footnote 73} What is being distinguished is that which is custom from that which is usage. Whereas a custom is defined as “a clear and continuous habit of doing certain actions which has grown up under the aegis of the conviction that these actions are, according to international law, obligatory or right,” ^{Footnote 74} a usage merely indicates “a habit of doing certain actions which has grown up without there being the conviction that these actions are, according to international law, obligatory or right.” ^{Footnote 75} As will be explored later, opinio juris is often considered to provide the key to distinguishing between custom and usage.

The idea of “legitimate expectations” also appears in the work of many scholars as a means of explaining the concept of opinio juris or as an alternative standard for determining the subjective belief of states with respect to the obligatory nature of their actions. ^{Footnote 76} For Mendelson, the use of “legitimate expectations” to identify rules of customary international law is directly linked to what he identifies as the most central and foundational norm to the international legal order itself: “States should comply with the legitimate expectations of the international community.” ^{Footnote 77} The relationship between legitimate expectations and opinio juris will be further examined below.

Anthea Roberts has argued that there are in fact different processes of customary international law formation: traditional customary international law and modern customary international law. ^{Footnote 78} Traditional customary international law follows the process identified in the North Sea Continental Shelf cases: “[G]eneral and consistent practice followed by states from a sense of legal obligation.” ^{Footnote 79} In this traditional process, state practice is prioritized, while “[o]pinio juris is a secondary consideration invoked to distinguish between legal and nonlegal obligations.” ^{Footnote 80} Traditional custom formation, according to Roberts, “is derived from specific instances of states practice.” ^{Footnote 81}

Conversely, modern customary international law “emphasizes opinio juris rather than state practice” and is therefore a “deductive process that begins with general statements of rules rather than particular instances of practice.” ^{Footnote 82} Roberts identifies the ICJ’s judgment in Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) as a good example of deductive modern customary law reasoning. ^{Footnote 83} She notes that “[t]he Court paid lip service to the traditional test for custom but derived customs of non-use of force and nonintervention from statements such as [UN] General Assembly resolutions.” ^{Footnote 84} Furthermore, the court’s analysis in its judgment gave limited consideration to state practice, instead finding that “it was sufficient for conduct to be generally consistent with statements of rules, provided that instances of inconsistent practice had been treated as breach of the rule concerned rather than as generating a new rule.” ^{Footnote 85}

I would, perhaps, interpret this attention to statements and the use of practice and opinio juris in the Military and Paramilitary Activities case slightly differently to Roberts. Many scholars consider statements, or verbal acts, to be examples or evidence of state practice, ^{Footnote 86} which, as such, weakens Roberts’ claim that greater emphasis was necessarily put on opinio juris as opposed to state practice. Instead, it appears that the issue in this case was that there was significant practice — in the form of verbal acts — supporting a customary rule of non-intervention. However, there was inconsistency among the physical acts. Therefore, the court seems to have adopted a “do as I say, not as I do” approach in determining the weight to accord to the evidence available in the case. As such, it is not necessarily clear that there is as significant a shift in balancing evidence of practice and opinio juris as Roberts suggests.

Roberts also notes an increase in “moral customs” in the development of modern customary international that can explain the shift in emphasis towards opinio juris and normative substantivity since “[m]oral customs are more normative than descriptive because they prescribe future action based on normative evaluations of ideal practice.” ^{Footnote 87} The development of moral customs, or customs influenced by morality, of course, is not an entirely new development, with international humanitarian law having a long history of incorporating humanitarian, or moral, concerns into its custom and practices. Since 1945, the development of human rights law and environmental protection has also been largely influenced by moral concerns. ^{Footnote 88} Roberts concludes that what is necessary in customary international law development is a balancing of practice and principles that must be regularly reassessed. ^{Footnote 89}

Ultimately, customary international law, whether traditional or modern, requires a determination of state practice and a subjective element, with room to vary the weight attributed to each. The formation of customary international law is a continuous one wherein custom develops, and may change, over time. ^{Footnote 90} It is an informal process, ^{Footnote 91} as compared to the formality of treaty negotiation and ratification, but it is a process that still “operates in a manner which ensures that the interests of all States are taken into account.” ^{Footnote 92}

State Practice

The first key element of customary international law is state practice, often referred to as the “objective” element. ^{Footnote 93} As previously noted, the emphasis of traditional customary international law has been on the consideration of state practice. ^{Footnote 94} Furthermore, the practice that is considered is that of states and the governmental bodies thereof, with non-governmental actors only able to influence indirectly insofar as their actions and interactions influence the practice of states. ^{Footnote 95} Governmental bodies may include the practice of international organizations composed of state representatives, such as the UN General Assembly. ^{Footnote 96} There is no indication of a precise number or percentage of states that must exhibit the practice. Furthermore, it appears there need not be a majority of states subscribing to the practice, with the number of supporting states/acts varying depending on the existence of practice conflicting with the potential rule under consideration. ^{Footnote 97} Consideration does need to be made to the practice of states “whose interests are specially affected” by the rule under consideration. ^{Footnote 98} This was articulated in the North Sea Continental Shelf cases with regard to the issue of continental shelf/territorial waters delimitation, naturally meaning that coastal states would be particularly affected and land-locked states would not.

The sources that may provide evidence of state practice most definitely include “physical acts (such as arresting individuals or ships).” ^{Footnote 99} However, verbal acts can also count as state practice and are often more common than physical acts. ^{Footnote 100} The 2000 ILA report provides a non-exhaustive list of verbal acts that can constitute state practice. It states:

As the ILA report notes, “[t]here is no inherent reason why verbal acts should not count as practice, whilst physical acts … should.” ^{Footnote 102} Furthermore, unilateral declarations by states were identified as being potentially binding practice by the ICJ in Nuclear Tests (Australia v France). ^{Footnote 103} In order for a “verbal act to count as State practice, it must be public — not in the sense that it need necessarily be communicated to all of the world, but that, if it is not publicized generally (e.g. by legislation, press statements, etc.), it must be communicated at least to one other State.” ^{Footnote 104} This reflects the need for states to have the ability to object to, or support, a developing practice that could evolve into customary international law; this opportunity being the key to customary international law’s binding character emanating from tacit agreement or consent on the part of all states. ^{Footnote 105} However, it can be difficult to find evidence of state practice since such things are not always widely publicized or communicated to other states, and, therefore, a determination that a rule of customary law exists will rarely, if ever, be based upon all state practice. Instead, such determinations can only ever be based upon the available evidence. ^{Footnote 106}

What practice is available to be considered is generally expected to be “widespread and representative” as well as “extensive and virtually uniform.” ^{Footnote 107} Mendelson has described “uniform” as meaning that practice should be “essentially similar and consistent.” ^{Footnote 108} Furthermore, it would appear that these standards do not require practice to be identical in all respects; that “they are sufficiently similar in important respects” would seem to be sufficient sometimes to meet the requirement. ^{Footnote 109} For example, Mendelson notes that the ICJ held that exclusive economic zones (EEZ) had become part of international customary law, even though “the various proclamations … [were] not identical.” ^{Footnote 110} Practice deviating from a custom (or potential custom) will not necessarily negate its creation or existence. ^{Footnote 111} This was demonstrated by the ICJ’s decision in Military and Paramilitary Activities where the court had to consider deviations from the rule of non-intervention. The court stated that it was

Finally, the practice in question need not span a considerable period of time. In the North Sea Continental Shelf cases, the ICJ stated that “the passage of only a short period of time is not necessarily, or of itself, a bar to the formation of a new rule of customary international law.” ^{Footnote 113} For example, Judge Lachs provided the example of the freedom of outer space, which had become a rule of customary international law “within a remarkably short period of time.” ^{Footnote 114} Consequently, though highly unlikely to be formed spontaneously or instantaneously, a rule of customary international law may form over a relatively short period of time.

Corporate Practice

The practice of corporations in the field of CSR has seen significant growth over the years. Zerk asserts that “[m]ost, if not all, leading companies now have strategies relating to CSR.” ^{Footnote 115} Kerr, Janda, and Pitts also cite numerous studies that demonstrate the growth of CSR, with studies showing that, in 2006, 90 percent of the top 100 European companies were publicly reporting on CSR issues, followed by 61 percent of the top 100 American companies and 59 percent of the top 100 companies from other parts of the world. ^{Footnote 116} They also refer to a 2007 Canadian study that found that 80 percent of the companies listed on the Toronto Stock Exchange issued reports containing information on CSR issues. ^{Footnote 117} Another example of the ever-increasing absorption of CSR into transnational corporate culture can be seen in the Global Reporting Initiative (GRI). The GRI is “an independent, multi-stakeholder network which has developed a voluntary sustainability reporting framework.” ^{Footnote 118} When it was first initiated in 1999, a mere twenty organizations were using this reporting framework, whereas by 2008 more than 1,500 corporations were employing the GRI framework in their reports. ^{Footnote 119} As noted, there is no precise number or majority rule for determining how much representative practice is required to form customary international law. Nonetheless, the figures in these studies demonstrate a significant amount of support and are therefore persuasive and noteworthy.

Corporations employ a variety of tools to incorporate, as well as to publicize, their CSR initiatives. These can include press releases and statements, advertising, websites, independent corporate initiatives, industry association initiatives, and global initiatives. One of the most common tools used by corporations to incorporate policies of CSR into their corporate structure is a code of conduct. These codes “generally deal with issues of consumer concern (including labour and environmental standards), legal compliance, and the issue of corporate risk (including bribery and corruption as well as human rights obligations. ^{Footnote 120} Zerk notes that “[m]ost leading multinationals now have a “human rights policy” displayed somewhere on their websites.” ^{Footnote 121} Corporations have also begun to publicly endors international human rights instruments. ^{Footnote 122} It must be noted, however, that many CSR codes of conduct and other initiatives are often accompanied by the label “voluntary.” While this is an important consideration in examining the potential for corporate customary international law formation, its effect must be considered in the context of opinio juris. Voluntariness is a matter of subjectivity and does not change whether an act/practice occurs or not.

The variation between different codes and initiatives is also frequently noted. ^{Footnote 123} The “subject matter, style and specificity” of these instruments can and do vary from company to company, or from industry to industry, although industry-wide or global instruments will often provide evidence of widespread and consistent practice. Such variation between companies and industries, however, does not prevent the identification of sufficient practice for the formation of customary rules. As seen in the context of EEZs, the practice need not be identical throughout; it need only be “sufficiently similar in important respects.” ^{Footnote 124} Despite variations, there are often many similarities within these instruments. For instance, Kerr, Janda, and Pitts identify seven principles they deem pervasive and common throughout a vast quantity of CSR initiatives. ^{Footnote 125}

In 2000, the UN launched the UN Global Compact, a non-state actor initiative providing a platform for business, civil society, and labour organizations to “advance their commitments to sustainability and corporate citizenship.” ^{Footnote 126} Currently, it is composed of over 8,000 companies and 4,000 non-business members spanning more than 160 countries. ^{Footnote 127} The compact advances “ten universally accepted principles in the areas of human rights, labour, environment and anti-corruption.” ^{Footnote 128} While there is no evidence that the phrase “universally accepted” was used to advance or allude to a notion of customary international law, one will note this striking parallel to language used in customary international legal discourse. Similar to some other instruments of CSR, the principles of the UN Global Compact are billed as non-binding, and many corporate members of the compact have been criticized for violations of the compact’s principles. ^{Footnote 129}

However, this does not negate the UN Global Compact’s value as a contribution to establishing rules of corporate custom. As referenced above and as will be reiterated below, the ICJ in Military and Paramilitary Activities stated that practice in the application of a rule of customary international law need not be perfect: “[C]omplete consistency” is not required. ^{Footnote 130} It went on to say that “the conduct of States should, in general, be consistent with such rules, and that instances of State conduct inconsistent with a given rule should generally have been treated as breaches of that rule, not as indications of the recognition of a new rule.” ^{Footnote 131} The UN Global Compact lacks any enforcement mechanism to employ against members who fail to always abide by the ten principles. The issue is the omission of enforcement and not one that vitiates the potential contribution to a body of corporate customary international law. Nonetheless, the UN Global Compact might be well advised to invalidate or withdraw membership from corporations who fail to abide by the principles.

The UN’s Guiding Principles on Business and Human Rights (UNGPs), which were presented in 2008 and unanimously endorsed by the Human Rights Council in 2011, present a less straightforward source to consider in the formation of corporate customary international law. ^{Footnote 132} Much like other instruments, such as the UN Global Compact, the practice of endorsing and operationalizing the content of the instrument most definitely construes relevant corporate practice. However, given that the final document is the product of the input of not only corporations but also other stakeholders, including states, individuals, and communities, it cannot be taken wholesale as being representative of corporate practice (or corporate opinio juris). The heavy reliance in the document on existing state-created law and regulation of corporations is without question important in terms of understanding existing legal obligations in the realm of business and human rights, but this must be distinguished from the separate body of corporate customary law proposed in this article that is strictly formed by the practice of opinio juris of corporations. Consequently, the UNGPs may provide greater evidence of corporate opinio juris through the contributions made by corporations in the consultation process rather than as a document demonstrative of corporate practice.

The wide array of initiatives and extensive implementation around the world of CSR provides ample opportunity to elucidate corporate practice on issues of CSR. In many respects, it may prove easier to gather evidence of corporate practice in the realm of CSR than to find evidence of state practice in certain areas of international law since corporations tend to publicize their actions more frequently than states.

State Opinio Juris

While state practice is considered the “objective” element in customary international law formation, it is not sufficient unto itself to create rules of customary international law. ^{Footnote 133} As such, the second element, often considered the “subjective” element, known as opinio juris, is required. Mendelson defines opinio juris as “a belief in the legally permissible or obligatory nature of the conduct in question, or of its necessity.” ^{Footnote 134} In the North Sea Continental cases, the ICJ described it as “a belief that this practice is rendered obligatory by the existence of a rule requiring it.” ^{Footnote 135} However, it does not require the express consent of each state to each rule of customary international law before that rule will be binding. ^{Footnote 136} This harkens back to the need to make public one’s actions since it provides the opportunity for other actors to object to the action or to support or acquiesce to it, even if that is done through their silence. ^{Footnote 137} As such, “whilst consent in such instances is a sufficient condition for being bound, it has never yet been held to be a necessary condition.” ^{Footnote 138}

Scholars have noted the very close interconnectedness, or intertwined nature, of practice and opinio juris. ^{Footnote 139} This can contribute to the difficulty in adducing opinio juris, which is compounded exponentially by the fact that, in many ways, it is impossible to know what states believe since they are “abstractions or institutions, [which] do not have minds of their own; and in any case, since much of the decision-making within Government takes place in secret, we cannot know what States (or those who speak for them) really think, but only what they say they think.” ^{Footnote 140} This has led to many scholars re-articulating the definition of opinio juris to emphasize the idea of “legitimate expectations” ^{Footnote 141} and to others limiting its relevance to distinguish between custom and usage — that is, between practice that is legally binding and that which is not. ^{Footnote 142} Michael Akehurst describes opinio juris as serving to distinguish practices that are obligatory from those that are performed for comity or courtesy. ^{Footnote 143} Another instance where opinio juris can be identified to demonstrate that a practice does not contribute to the formation of customary international law is where the state’s practice is accompanied by a disclaimer — that is, a statement that the act is done ex gratia or without prejudice. ^{Footnote 144}

Sometimes international instruments may be described as “non-binding” as is the case with declarations, such as the 1992 Rio Declaration on Environment and Development (Rio Declaration). ^{Footnote 145} In spite of initially being attached to this label, content in such instruments may still evolve to obtain customary international legal status. For example, principles of “common but differentiated responsibility” and “future generations” (the need to protect the environment for present and future generations) that are expressed in the Rio Declaration are now considered to have customary status. ^{Footnote 146} Mendelson goes so far as to state that there is no need to adduce evidence of opinio juris in cases “where there is a constant, uniform and unambiguous practice of sufficient generality, clearly taking place in a legal context and unaccompanied by disclaimers.” ^{Footnote 147} Instead, he proposes that the evaluation of the formation of customary legal rules should be considered in a “claim-and-response” rubric. ^{Footnote 148} This means, that the action of a state, whether physical or verbal, represents a claim of right, whether express or implicit, and the legality of the act hinges on the response of other states: acceptance or protest. ^{Footnote 149}

While the above discussion has tried to simplify opinio juris to its basic foundations, the concept has always been a notoriously tricky one to define, articulate, and identify. Despite this, customary international law is unquestionably “one of the main sources of [public international] law.” ^{Footnote 150} While firmly entrenched as a formal source of public international, it has nonetheless been the subject of numerous scholarly articles and reports by the ILA and the International Law Commission (ILC) as scholars and practitioners alike strive to better understand and improve the means for identifying, in particular, opinion juris as well as customary international law, more generally. ^{Footnote 151} In its 2014 report, the ILC unequivocally stated that regardless of this theoretical grappling with the element of opinion juris, its application in practice has not been blocked. ^{Footnote 152}

CSR: Corporate Opinio Juris

The complexities surrounding opinio juris discussed above naturally would continue to exist in the context of corporate opinio juris and corporate customary international law. This article does not attempt to offer a solution to these challenges, which have been contemplated by scholars and jurists for decades. However, it stresses that just as customary international law continues to be one of the most important sources of public international law, so could corporate customary international law be a useful source of law regardless of the ongoing questions and complexities in relation to the element of opinio juris. Much as many scholars employ the concept of “legitimate expectations” to convey an understanding of opinio juris, scholars in the field of CSR also employ this concept to explain the function of CSR norms. ^{Footnote 153} The need to maintain this licence or legitimacy creates an obligation to fulfil the types of duties contained in CSR instruments. As discussed, there exists ample evidence of corporate practice in the form of codes, policies, initiatives, and so on. Furthermore, publicized statements of corporations can also be looked to adduce the subjective element behind these acts. Nonetheless, there is often concern and scepticism when it comes to “matching words with deeds.” ^{Footnote 154} The case of Military and Paramilitary Activities suggests that in such cases an emphasis may be placed on words rather than on the acts that are inconsistent with those statements.

A second concern when it comes to identifying corporate opinio juris is that, as alluded to earlier, so many CSR initiatives are labeled as being “voluntary,” a characterization with which many scholars take issue ^{Footnote 155} but which might also suggest a lack of opinio juris on the part of corporate actors subscribing to such initiatives. ^{Footnote 156} As demonstrated by the 1992 Rio Declaration, the content of instruments initially considered to be non-binding is not inhibited from evolving into rules of customary international law. Corporations may initially adopt a particular voluntary policy or code “for instrumental or strategic reasons,” only to find that adherence is “gradually maintained out of conviction that they are the appropriate basis for action.” ^{Footnote 157} Furthermore, many scholars challenge the suggestion that such instruments are indeed entirely voluntary once subscribed to — that is, the initial decision to accept the code or instrument is voluntary, but the choice to follow the provisions is not voluntary once subscribed to. Shifting levels of bindingness over time can complicate and “further erode the distinction between the law and ethics of corporate social responsibility.” ^{Footnote 158}

State Acquiescence and Persistent Objectors

While express consent is not necessary from every state for the formation of customary legal rules, the behaviour of states is important in determining the effect a new rule of customary law may have upon them. The general rule is that all states are bound by rules of customary law, whether they have taken part in the practice leading to its creation or not. ^{Footnote 159} If a state has expressly consented to the customary rule in question, then it naturally will be bound by it, but consent is rarely given explicitly in customary international law formation. ^{Footnote 160} Once again, the importance of publicizing practice (or claims of right) arises here because:

The absence of practice or protest will be interpreted as acquiescence — that is, acceptance — of the rule. ^{Footnote 162} Therefore, they will be bound by the rule along with the rest of the international community of states.

There is, however, a means by which a state can avoid being bound by a rule of customary international law. This is known as the “persistent objector” rule. The persistent objector rule states that “a State which manifests its opposition to a practice before it has developed into a rule of general international law can, by virtue of that objection, exclude itself from the operation of the new rule.” ^{Footnote 163} This opposition must be made early on in the formation of the rule in question; once the rule has been established, it is too late since it has already become binding. ^{Footnote 164} Furthermore, the objection/protest must be maintained and be persistent; if “it is abandoned it loses its effectiveness to prevent the rule becoming binding on the State.” ^{Footnote 165} Effectively, the persistent objector rule requires a state to actively opt out of a developing rule of customary law and continue to opt out once it has become a binding rule. ^{Footnote 166}

CSR: Acquiescence and Persistent Objectors

In the context of CSR, there is often concern about the issue of “free riders” — that is, corporations who seek to benefit from, for example, the reputational benefits of CSR practised by other corporations without themselves having to make changes to align their practices with CSR standards. ^{Footnote 167} If their actions, or inactions, were examined in the context of customary law formation, they would either be bound by the rule based on verbal statements amounting to consent or through acquiescence and failure to object. If these corporations absolutely opposed the idea of being bound by the rule or rules in question, they would have to publicly object to the practice early on and maintain this objection over time. If we consider the concern over “voluntary” codes and initiatives, it may, at most, suggest opposition at the outset when first subscribed to, but, in order to remain non-binding, corporations would have to repeatedly assert that they are opting out of the practices in question. For example, the International Council on Mining and Metals (ICMM) has an association set of standards, or best practices, that they make widely available to members and non-members alike. ^{Footnote 168} The publicizing of these standards provides widespread knowledge to other corporations that they are claiming this to be the best practices and applicable standards for operation. In order for other corporations, particularly non-members of the ICMM, to avoid being bound, they would have to publicly object or opt out.

Particular/Regional Custom

There is a subset of customary international law that deserves mention and has potentially important relevance to the idea of corporate customary international law and that is particular or regional custom. In certain instances, a practice will exist or develop among a limited “number of states (even to two only) and [be] accepted as law by them.” ^{Footnote 169} In such cases, this will be a customary rule of particular application, binding only between the few states in question. ^{Footnote 170} In the context of corporations, this development would provide room for industry-specific, and, if necessary, region-specific, customary rules to develop. This is important because the types of CSR concerns that arise in one context — for example, mining — may at times differ from concerns arising in another context — for example, textile manufacturing — or, for instance, the concerns of companies operating in Latin America to those operating in Europe.

Application and Enforcement of Customary International Law

In terms of its enforcement, customary international law is widely enforceable in international courts and tribunals. The enforcement may be a result of an explicit requirement, such as in Article 38(1)(b) of the Statute of the International Court of Justice, which states that the court “shall apply … b. international custom, as evidence of a general practice accepted as law.” ^{Footnote 171} The enforcement may also be the product of an implicit requirement such as in the Statute for the Special Court of Sierra Leone, which gives the court jurisdiction over “serious violations of international humanitarian law and Sierra Leonean law,” implicitly including the extensive body of customary international law within international humanitarian law. ^{Footnote 172} Finally, the required enforcement of customary international law may be conditional, as in the case of the International Tribunal on the Law of the Sea (ITLOS), which is directed to apply its enabling convention as well as “other rules of international law not incompatible with [that] Convention.” ^{Footnote 173} It must be noted that, while international courts and tribunals have the ability and often the requirement to consider and apply customary international law, the subjects to which their jurisdiction to adjudicate matters is aimed will be limited. The ICJ adjudicates matters between states who have accepted its jurisdiction; ^{Footnote 174} the Special Court of Sierra Leone has jurisdiction over individuals bearing the “greatest responsibility” for violations of international humanitarian law in Sierra Leone since 30 November 1996; ^{Footnote 175} and ITLOS has jurisdiction over disputes under the UN Convention on the Law of the Sea from states parties to that Convention. ^{Footnote 176} There are very few international adjudicative bodies with jurisdiction over corporations, with most bodies limited to jurisdiction over either states or individuals or, on occasion, both states and individuals.

The rule for application or enforcement of customary international law in national legal systems is quite straightforward: all national legal systems deem customary international law to be automatically incorporated into national law. ^{Footnote 177} As Antonio Cassese notes, “[this] is the only suitable [implementation system] for rules that emerge gradually in the world community and whose content is not immediately definable.” ^{Footnote 178} Once a customary rule has crystallized, it is law, not only in the realm of the international community but also in the realm of domestic law within individual states. Of course, the point at which a rule of customary law is formed is not always clear. This can pose difficulty for national courts where an authoritative international pronouncement, such as from the ICJ, has not yet been provided to identify that a rule has indeed reached the point of crystallization. In such instances, it will be left to the national court to evaluate state practice and opinio juris and determine if a customary rule has indeed been formed. There are many countries in which the courts have jurisdiction over corporations as well as over individuals and the government; therefore, unlike under international law, there are would be opportunities in many, though not all, states to apply customary international law to cases involving corporate defendants. ^{Footnote 179}

Advantages of Corporate Customary International Law

Corporate customary international law has the potential to overcome or address four key concerns faced by the contemporary international legal system. First, as mentioned, it can help to eliminate the problem of “free riders” or “empty promises” by requiring corporations to publicly opt out if they wish to avoid being legally bound by CSR duties. Second, it addresses concerns currently hindering state-led legislation of CSR. This includes the tension over which state, the home state (state of incorporation), or the host state (state where operations take place) has responsibility for legislating on CSR issues. Hesitation is often said to be tied to the fear of infringing on the other state’s sovereignty. ^{Footnote 180} States are also often hesitant to over-regulate commercial activity in their jurisdiction for fear of damaging their own competitiveness and economy. Third, the flexibility and ongoing development of customary international law allows the law to evolve alongside societal developments. It also avoids binding all corporations to a “one-size-fits-all” approach, which is disliked by the corporate community and also a common characteristic of government regulation. ^{Footnote 181} The potential for regional or industry-specific rules of customary law to develop is key to preventing a “one-size-fits-all” approach. Finally, corporate customary international law makes corporations directly accountable for violations of, in particular, human rights and environmental protection that is central to CSR, which recognizes and addresses global developments that have resulted in corporations having unprecedentedly large impacts in these areas.

Problems or Ongoing Concerns with This Approach

While corporate customary international law has the potential to address many concerns, there are still some remaining concerns. First, the feasibility of this approach would still require recognition. State recognition of the existence of corporate customary international law could accelerate the process of implementation. Without state recognition, the requisite recognition is still possible, though likely to be very slow and reliant on national and regional courts to gradually recognize that certain principles of CSR are in fact binding. Second, even with state recognition, there is currently no international forum for states or individuals to hold corporations accountable for violations of CSR, and, therefore, they would still be reliant on national and regional enforcement. ^{Footnote 182} Third, even with states recognizing the existence of corporate customary international law, it would not guarantee that states would actively pursue the enforcement of these laws. As such, there is the risk of perpetuating the current regulatory stagnation seen in the home/host state debate in a slightly different context. Finally, even if state recognition occurred and states were willing to enforce these laws, there is the risk that corporations would avoid CSR obligations through the persistent objector rule. While this seems unlikely given the assumption of high reputational costs for such action, the worst case scenario would be that some corporations would openly and transparently declare that they would or would not accept CSR standards as legitimate and binding obligations. At worst, it would align words and actions.