A. The Concept of Accountability in International Law
1 Accountability is a term that (international) law shares with several cognate disciplines. It also prominently features in political science and international relations (Keohane, 2006, 75) as well as economics and moral philosophy. In law, accountability has its deep historic roots in many domestic legal orders. In what follows, the discussion will concentrate on accountability in modern international law. As will become clear, the present evolutionary stage of international law—as regulatory and as procedural—has provided a strong impetus for generalizing international accountability.
2 The starting point of thinking conceptually about accountability is the freedom of individuals or the competence of a holder of public authority. Both freedom and competence indicate choice protected by law. This choice is the precondition for any meaningful suggestion of accountability. Accountability refers to constraints on this choice, to its exercise by an actor in accordance with certain parameters. The idea of accountability thus implies a relationship between actors. The matrix of this relationship comprises the three vectors of who is accountable for what and to whom (Bovens, 2007, 447; Curtin and Nollkaemper, 2005, 3).
3 Who, then, is accountable in international law? International law, even at its present stage of development, rests on sovereign states for which the principles of equal sovereignty, territorial integrity, and comprehensive international legal personality provide a large measure of competence or freedom to act. Therefore, states are primarily accountable under international law. International organizations all respond to the constructive principle of limited or attributed competences. That principle, in turn, limits the accountability of international organizations to the extent of their competences and how they are exercised. Finally, the current evolutionary phase of international law is marked by a much broader regard for non-state actors. Individuals as well as companies had been viewed as being largely mediated by states, even though international law had guaranteed their freedom to act through human rights law, including for commercial activity. In a marked development, individuals and companies are moving into a position where the corollary, the accountability for the exercise of that freedom becomes more perspicuous under international law.
4 Accountability is linked to a specific conduct, the accountability for what. The standard for this conduct can be determined morally and politically. In a rule of a law-based system, it will eventually be determined by law. That is also the case for international law. The concept of accountability then, is directly related to the modern institutionalized process of international policy and law-making. This bindingness-creating process for the formalization and authorization of norms into rules is grounded in the practice of states, and enables more dynamic policy and law-making than in the past.
5 Accountability necessarily implies someone else, the accountability to whom. In the international context, this must be another international actor. In the absence of a central organization, accountability lies ultimately with the international community of states which represents humanity. The international community of states acts through international organizations both universal and regional, or functional equivalents such as meetings of parties to multilateral law-making treaties which are also both universal and regional.
6 Finally, accountability cannot exist without proper procedures and mechanisms; absence of those mechanisms means an absence of accountability. Accountability then, cannot exist without transparency. Transparency is a necessary condition of accountability (Peters, 2013, 607). Accountability also implies that there are sanctions in one form or another should the conduct be found to fail to reach the required standard. The increasing focus of international law on procedure has an important consequence here. It includes continuous production and improvement of practices, instruments, and methodologies to realize accountability in a sector-specific manner. International courts and the customary law of state responsibility serve as general accountability mechanisms.
7 Defined by this three vector-matrix, accountability becomes an institution of international law. An institution of law is based on an idea about the law. An institution, such as accountability, is not deontological or law-producing in itself. In order to be formalized into binding law, it depends on subsequent law-making and administrative and judicial decision-making that instantiate the institutional idea. Such instantiation may rely on a process of international lawmaking that has been formed through actual practice. It starts out with the consensus of the international community of states on goals and norms that then trigger successive rounds of international rule-making through both treaty and infra-treaty instruments at the international and regional level which produce customary international law binding on all states by accumulating sufficient instances. The process has as its starting point universal master-norms that guide all states in their internal and external actions. It is the universally representative United Nations General Assembly (‘UNGA’) that has the authority as well as the legitimacy to accept such master-norms in a resolution that will often fixate the outcome of a universally attended conference of states. Sustainable development, human dignity, collective security, and the self-determination of peoples form such master-norms. Acceptance of a master-norm triggers acts of concretization and authorization into binding international law, which in turn are norm-affirming. This process employs the traditional sources of international law, in particular treaties, increasingly supplementing those with what may be called infra-treaty instruments. Such instruments comprise, among others, decisions of the meetings of parties to major multilateral treaties, treaty-concretizing court decisions, and arbitral awards, and international organizations exercising their oversight function under law-making multilateral treaties. On the basis of this process, accountability can become institutionalized throughout the entire scope of international law.
8 Accountability has a close conceptual connection with responsibility. Responsibility can be understood in the narrower, technical sense of the international responsibility of states for wrongful acts. This branch of customary international law establishes which secondary obligations arise for a state that violates its primary obligations. Based on the reciprocity of international obligations, it is a general mechanism providing legal sanctions for noncompliance. The mechanism is decentralized as these sanctions become the responsibility of certain other states. It can be used only by the state that the obligation was owed to, or in the case of obligations owed erga omnes or erga omnes partes by one state acting for all states. Those sanctions take two principal forms. Other states may take countermeasures, that is they may themselves violate an obligation with the aim of bringing about the lawful behaviour of the first state. Alternatively, those other states may request cessation of the unlawful behaviour and reparation for the consequences of non-compliance. The customary law of the responsibility of international organizations for unlawful acts is constructed along similar lines. International responsibility for unlawful acts provides a decentralized accountability mechanism that is always available to hold states to account for compliance with international law (Brunnée, 2005, 21). States can employ it in a discretionary manner, based on the autonomy of each state in evaluating international lawfulness. In contrast, the idea of accountability leads to the setting up of organizations and institutionalized ways of determining lawfulness and the sanctions for unlawfulness.
9 Responsibility can also be understood in a broader sense, rather than the said technical international responsibility of states and international organizations for a violation of their legal obligations (Roeben, 2007, 1389). Understood in such a broader sense, responsibility overlaps with accountability. Akin to accountability, the idea of responsibility also connects two actors and a required course of action that is potentially laid down in law. Responsibility hence comprises accountability and vice versa, although accountability emphasizes the element of accounting and sanctioning/punishment.
10 While the international law of state responsibility operates in the sphere of horizontal state-state relations, accountability also overlaps with the rights of the human person. International human rights set standards for required conduct that states are to adopt, generally expressed as the obligations to respect, protect, and promote and for which they are accountable, ultimately through judicial protection. Each human right has an intrinsic standard-setting function, defining for instance the protected space of free communication in a society. But human rights are also capable of absorbing extrinsic standards. This reinforces the normativity of that standard. Human rights are mobilized to ensure effective accountability of national legislative, administrative, and political organs for broad policies as such rights are enforceable before national courts. For instance, a second-generation human right to a healthy environment, or a first generation right to private life, absorbs and enforces international environmental law standards in this sense.
12 Finally, accountability has become an important topos in the legitimacy of international law and international organizations. For much of the history of international law, legitimacy had not been the focus of controversial attention beyond state consent. This has changed in the current, regulatory development phase of international law. In contrast to Max Weber’s descriptive concept of legitimacy (legitimitätsglaube), the normative concept of legitimacy is related to the justification of authority. It refers to some benchmark of justification of political power and the law that this power authorizes. For many, accountability is one such benchmark in a domestic context. While the literature has not reached this conclusion, there is in principle no reason to deny that accountability should also be such a benchmark in the international context if the critical conditions become comparable. This is arguably the case for modern regulatory international law. This regulatory international law develops legal directives to achieve globally shared public objectives, for instance action to limit climate change through a transition to a sustainable energy system. It also has a much higher capacity for addressing private parties directly and indirectly. Such role and capacity of international law, however, creates an acute concern for the foundations of its legitimacy in addition to state consent (Buchanan and Keohane, 2008, 25), including not only accountability of states and of international organizations as holders of international public authority, but possibly also of those private actors whose cross-border economic activity is enabled by international law.
13 The following considers the accountability matrix of the relevant actor categories, states, international organizations, and finally individuals and companies, discussing to whom each is accountable and for what action.
B. Accountability of States
14 The modern accountability of states is aligned with the rise of shared values, interests, and then goals and objectives. This rise mirrors the evolution of international law from a law of coordination to a law of cooperation and then to a law of regulation. This law of regulation is marked by a focus of the international community of states on its common objectives and how to achieve them through strategies that result in a joint effort of all states.
15 The linchpin of these strategies are master-norms. These constitute the normative consensus of the international community of states regarding a desirable economic, environmental, social, and humanitarian state of affairs. They determine the required conduct of states, internally and externally. The expectation to act towards achieving these master-norms is directed to all states at their various stages of development. Such master-norms are the Sustainable Development Goals (‘SDGs’) and the 2030 Agenda (2015), the Vienna Declaration of Human Rights (1993), the Responsibility to Protect (2005), and the 2018 Global Compact on Refugees. The 2030 Agenda as well as the Vienna Declaration and the Responsibility to Protect resolution all exhort states to cooperate closely in the sense of further law-making to concretize these norms. The common feature of these master-norms is that they define standards of accountability of all states for broad policies. It should be noted that these master-norms are comprehensive of all state activity and hence support the claim that accountability is an institution for all international law.
16 The accountability of states under these strategies lies with the United Nations (‘UN’). It is organized through the principal organs of the UN, the UNGA, the Economic and Social Affairs Council (‘ECOSOC’), and the UN Security Council (‘UNSC’). This is true for the SDGs. Accountability of states thereunder lies to the High-Level Forum (‘HLF’) operating under the auspices of ECOSOC and the UNGA. The principal instrument to realize the accountability of individual states is the voluntary Policy Review process. Through it, each state gives account of its policy against the SDGs to the HLF. Underneath it, the entire UN machinery supports the SDGs, and is developing sectoral methodologies to hold states to account. Accountability for human dignity lies with the UN Human Rights Council (‘UNHRC’), an organ of the UNGA. Accountability for the fundamental humanitarian standards that are safeguarded by the Responsibility to Protect ultimately lies with the UNSC, which as a last resort may intervene through forcible measures.
17 This accountability of states against the SDGs, the Responsibility to Protect, and human dignity, is institutionalized in a legally binding manner by multilateral law-making treaty. Such treaty concretizes the three axes of the accountability matrix. It concretizes the parties, the standards, and the organization with which accountability lies. The starting point is that the treaty identifies the ‘common concern’ over a priority area. The meaning of this term has remained somewhat contentious, but essentially it denotes a competence claim of the international community of states to achieve a common objective, to bring all states together for this purpose, to set legally binding standards, and to organize itself. Therefore, it is the responsibility of all states to work towards, adopt, and implement these standards, and be held accountable. This responsibility is common to all states, even if it is differentiated between states on the on a secondary level of varying stages of development. The treaty then establishes the organization and procedure for further infra-treaty rule-making and also for compliance control.
18 The UN Framework Convention on Climate Change (‘UNFCCC’ or ‘the Convention’) (1992) exemplifies this legally concretized accountability for the priority area of international climate action. The convention has attracted and retained near universal membership, and the implementing agreements, the Kyoto Protocol (1997) and the Paris Agreement (2015), strive to maintain that universality. The Convention defines the global climate as a common concern, and then determines the common but differentiated responsibility of states parties for taking protective action. Under the Paris Agreement, each state party is accountable for its contribution to the collective effort towards the objective of limiting global temperature rise, as assessed in the ‘Global Stocktake’ carried out by the meeting of the parties to the Agreement. This accountability of states parties is formalized as the obligation to formulate and submit a so-called nationally determined contribution in accordance with an agreed template. But states remain accountable for taking further suitable measures to achieve the agreed objective. Under the Convention and its implementing agreements, each state party is accountable in this sense to the collectivity of states parties, organized in a conference of the parties to the convention (‘COP’) or a meeting of the parties to the implementing agreements of the convention, the Kyoto Protocol (CMP) and the Paris Agreement (CMA). Each state then has to integrate the results of this assessment into the next periodic pledge. Continuous accountability is operationalized through a dynamic procedure.
19 Legally concretized accountability of states also applies to governance of the oceans. Unlike the international law on climate change, the 1982 UN Convention on the Law of the Sea (‘UNCLOS’) makes no express reference to the responsibility of states, but the International Tribunal for the Law of the Sea (‘ITLOS’) nevertheless has established that states parties are responsible for achieving certain collective objectives of ocean policy. This responsibility complements the broad competences that the convention allocates to states. In the Advisory Opinion Submitted by the Sub-Regional Fisheries Commission (‘SRFC’) of 2015, the ITLOS established this for the flag state. While the UNCLOS vests flag states with the exclusive jurisdiction over their ships, the Tribunal emphasizes the accountability of the flag state for the exercise of this jurisdiction in line with objectives of the UNCLOS. This accountability lies with UNGA and to the competent regional fisheries organization. That organization is therefore empowered to make the concretizing rules on protecting fisheries against unregulated activities, which the vessel is to comply with, and also for sanctions in cases of contravention. In Responsibilities and Obligations of States Sponsoring Persons and Entities with respect to Activities in the Area (2011) the Tribunal pronounced in a parallel manner on the responsibility of the state sponsoring deep seabed activities of a private party.
20 The accountability of states regarding objectives of the international community of states is institutionalized not necessarily through a single foundational law-making treaty. This can also be achieved through a legal regime that integrates a specific treaty with non-specific treaties. Such is the case for energy. Access for all to sustainable energy has emerged as such an objective, anchored in SDG 7. The Energy Charter Treaty (1998) defines specific standards for the energy policy of states, complemented by a growing range of energy-related provisions under non-specific international law, including preferential trade agreements.
21 The accountability of states for their legal obligations is ideally secured through a third-party dispute settlement. It is transparent and effective particularly in asymmetrical power relations. The preference translates into a trend in international law to institutionalize adjudication or arbitration with compulsory jurisdiction. The International Court of Justice (‘ICJ’) has effectuated this trend by recognizing that multilateral law-making treaties create erga omnes partes obligations that every state party has an interest in and standing to enforce (Application of the Convention on the Prevention and Punishment of the Crime of Genocide, Gambia v Myanmar, 2020). The preference for this type of dispute settlement also means that there should not be jurisdictional gaps for foundational standards in international law. For such standards, there emerges a principle of residual institutional jurisdiction in the form of the general advisory jurisdiction of the ICJ or the sectorial advisory jurisdiction of ITLOS. It is residual in that lack of consent is not a bar. That principle has been instantiated for compliance with the international law of self-determination of peoples based on Article 2 UN Charter. The ICJ advisory opinion in Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965 (2019) (‘Chagos case’) confirms this. Neither the sovereignty issues involved, nor the absence of consent proved a bar to this jurisdiction as they had been for the contentious jurisdiction of the arbitral tribunal under Part XV UNCLOS in the Chagos case (2015). Ensuring judicially administered accountability becomes a common thread uniting the organizationally plural international judicial architecture (Boisson de Chazournes, 2017, 13).
22 Accountability through courts, arbitral tribunals, or quasi-courts with compulsory jurisdiction secures accountability of all states parties under multilateral treaties. It suffers a set-back when new concepts of sovereignty and bilateralism carve out a space for bilateral arrangements, unilateral enforcement mechanisms, or an agreement of the parties not to seize the multilateral third-party dispute settlement machinery. This replaces institutionalized accountability with tit-for-tat.
C. Accountability of International Organizations and International Courts
23 States are accountable to the international community of states, which acts through international organizations. In turn, international organizations are accountable (Hafner, 2003, 236; Reinisch, 2001,131). This accountability lies, first of all, to the Member States. International organizations are accountable to the Member States for the exercise of their functions and competences under the constitutive instruments. The organization and procedure of that accountability is specific to each organization (Ong and Sheldon, 2011). International organizations may be held accountable for actions of their staff, and in turn may hold their staff accountable (Dean, 2005, 97). The accountability of an international organization may also lie to an individual state, even though the immunity of the organization is a bar to the enforcement of that accountability (Reinisch, 2005, 119). This accountability of international organizations before national courts is one of the most difficult problems particularly in EU law and the constitutional law of EU Member States.
24 International courts and tribunals are sometimes organized as international organizations. As such, they are also accountable to their members. The premier function of courts and tribunals is to assist States in settling their disputes. It is not necessarily the maintenance of the rule of law. This accountability of courts and tribunals entails a responsibility to concretize open-textured principles in international law.
26 The accountability of international courts and tribunals to states consenting to their jurisdiction is closely linked to general organizational and procedural standards that ensure that decision-making is transparent and legitimate. The demand for such standard is driving the ongoing negotiations, under the auspices of UNCITRAL, for a reform of international investment arbitration.
D. Accountability of Individuals
27 Under modern international law there is also the accountability of individuals. The idea of an international criminal law is based on the notion that individuals are accountable to humanity for those ‘most serious crimes of concern to the international community as a whole’. As the Rome Statute of the International Criminal Court (1998) (‘ICC’) formulates it, these crimes—genocide, war crimes, and crimes against humanity that may also be committed by individuals in their capacity as state officials—are of international concern. Under the principle of complementarity, this individual accountability is implemented first by national courts and, in a subsidiary manner, by the ICC. Thus, this accountability is sanctioned internationally. The jurisdiction of the ICC depends on the consent of states based on the traditional principle of territoriality, with the important exception that the UNSC may refer a situation in a non-member state conferring international jurisdiction on the Court. The mandates of other existing international or mixed international/national criminal tribunals-including those for Cambodia, Lebanon, the former Yugoslavia, Rwanda, and Sierra Leone are limited to certain geographical areas. They were established by UNSC resolutions or by agreement between the UN and the state concerned. It is indeed an important conceptual advance that this accountability of individuals pierces the veil of the state. It does so particularly powerfully for the crime of aggression, a leadership crime, to which the Kampala amendment (2010) extends the jurisdiction of the ICC, albeit under limiting conditions.
29 In its jurisprudence, the ICJ has much strengthened this decentralized accountability mechanism. In Obligation to Prosecute, having identified states parties’ power under the CAT to prosecute for torture, the Court finds a need for the state to exercise that power rather than to choose either to prosecute or extradite (Questions relating to the Obligation to Prosecute or Extradite, Belgium v Senegal, 2012, paras 98–95). In the Wall Advisory Opinion, the Court identifies that all states have the jurisdictional power to prosecute under the Fourth Geneva Convention, and also finds a need for the state in such position to do so (Legal Consequences of the Construction of a Wall in Occupied Palestinian Territory, 2004, para 159). As a result, states have to exercise their universal jurisdiction, curtailing discretionary choices not to do so. This decentralized accountability mechanism has its limits in other overriding values of international law, in particular unhindered state-state communication through their officials as the ICJ made clear in Arrest Warrant of 11 April 2000, Democratic Republic of the Congo v Belgium (2002). This case settled this question regarding personal immunity. The pending case Immunities and Criminal Proceedings, Equatorial Guinea v France, will address the functional immunity of state officials.
30 Yet individual accountability also exists for broader collective objectives of the international community. The UNSC interprets the term ‘international security’ under the UN Charter widely. It has declared international terrorism and the proliferation of weapons of mass destruction to be a threat requiring action on a ‘global level’. On that basis it holds responsible individuals to account, listing and sanctioning them by freezing their assets. The Kadi-cases at the European Court of Justice confirm that such individual accountability to an international body presupposes that that body respects standards of judicial protection. This central accountability is complemented by decentralized accountability to states. Such de-centrally organized accountability underpins the numerous treaties for quasi-universal jurisdiction and judicial cooperation on matters ranging from anti-terrorism to organized crime. The underlying idea here is also that individuals responsible for certain cross-border acts are accountable to the international community of states. It is in fact the oldest layer of international individual accountability.
E. Accountability of Companies
31 In a relatively new development, companies that operate transnationally have become accountable internationally. The idea is that such companies become accountable for the respect of international concerns on human rights and on the environment. Doctrinally, the referenced human rights instruments were originally addressed to states. The required standard remains unchanged. But the accountable actor changes from the state to private actors.
32 This accountability has been specified in a non-binding form. In 2011 the UNHRC resolved the Guiding Principles on Business and Human Rights for implementing the UN ‘Protect, Respect and Remedy’ Framework (‘UNGP’), providing a standard for preventing and addressing the risk of adverse impacts on human rights linked to business activity. A set of recommendations outline how States and businesses should implement the framework in order to better manage business and human rights challenges. These principles may be concretized by a treaty although that remains controversial. A UNHRC working group has prepared a preliminary draft for a ‘Legally Binding Instrument to Regulate, in International Human Rights Law, the Activities of Transnational Corporations and Other Business Enterprises’ (2018). The UN Secretary-General has set out a mandate for the voluntary Global Compact to promote responsible business practices and UN values among the global business community and the UN System (2000). The ‘Ten Principles’ of the Global Compact are derived from human rights instruments, the Universal Declaration of Human Rights, the International Labour Organization’s Declaration on Fundamental Principles and Rights at Work, the Rio Declaration on Environment and Development, and the UN Convention Against Corruption. Transnationally active companies are expected to meet their responsibilities for human rights, labour, environment, and anti-corruption by incorporating the Ten Principles into strategies, policies, and procedures. Companies also have to satisfy themselves that their local partners have a so-called ‘social license’ to operate, for instance when mining the critical minerals used in the batteries that power electric vehicles.
34 Concretization and operationalization of international corporate accountability is taking place in sectors of international law. In international investment law, there is a broader reform of ‘modernization’ underway based on the concept that investors, mostly legal persons, engaged in cross-border direct investments are accountable not only to their home state but also to the host states for that investment to generate economic, social, and environmental benefits there. This accountability translates, inter alia, into a new generation of EU investment treaties that carves out of the protection standards for investment a space for legitimate host state regulation. In international human rights/criminal law, the (Malabo) Protocol to the African Charter of Human Rights, which has not yet entered into force, would vest the African Court of Justice and Human Rights with the jurisdiction to hear cases involving international crimes committed by corporations. In human rights law on the national level, in 2015 the Human Rights Commission of the Philippines initiated a Carbon Majors inquiry on the responsibility of global corporations for human rights violations or threats resulting from the impacts of climate change.
Volker Röben 
![Max Planck Encyclopedia of International Procedural Law [MPEiPro]](/view/covers/mpeipro.jpg)
