This chapter begins by introducing a number of foundational concepts, which serve as the starting point in the field of public international law. Section 1 of this chapter begins with the notion that states are sovereign equals, which must consent to be bound by nternational law. This section also introduces the critical distinction that international law makes between states and “non-state actors.” Section 2 of this chapter discusses the inevitable comparison of public international law with domestic legal systems, and the significant limitations of this analogy as a means for understanding the field of public international law. Section 3 concludes by explaining this book’s overarching structure, as well as the approach of this book to the introduction of public international law.

The rules of state responsibility are set out in the International Law Commission’s (ILC) Articles on the Responsibility of States for Internationally Wrongful Acts. This chapter introduces the basic features of the ILC’s Articles on State Responsibility, beginning with an explanation of what constitutes an internationally wrongful act. The following section discusses the circumstances precluding wrongfulness that may be invoked by states seeking to avoid responsibility for an internationally wrongful act. The chapter then covers the aftermath of an internationally wrongful act, which can involve legal consequences, such as reparations, as well as countermeasures. This chapter focuses specifically on the responsibility of states, rather than the responsibility of international organizations or individuals.

This chapter sketches the development of international human rights law. The legal position of individuals was perceived by states as a domestic affair of the sovereign state, which could effectively treat its citizens as it pleased. It was not until after the Second World War that this fundamentally changed and international law began to grant individuals rights to protect them from the state. The chapter further presents the main categories or generations of human rights and discusses their key characteristics. Human rights are generally organized in three categories or generations: (a) civil and political rights; (b) economic, social, and cultural rights; and (c) collective rights. This chapter will subsequently turn to several matters concerning the scope of human rights norms, including their addressees, their territorial scope of application, and the circumstances under which human rights may be restricted by the state. Finally, this chapter will explain how human rights are monitored and enforced under international law.

After a sketch of the history of the law of the sea and the traditional freedoms of the sea, this chapter discusses the various efforts to codify the law of the sea during the twentieth century, which culminated in the adoption of UNCLOS in 1982. Subsequently, the chapter examines the legal regimes governing the various maritime zones, as well as two international areas: the high seas and the Area. The chapter then takes up thematic issues in the law of the sea, namely the delimitation of maritime boundaries, the protection of the marine environment, the special interests of developing countries, and the system for the settlement of law of the sea disputes. The chapter concludes by noting that, despite the relatively comprehensive scope of UNCLOS, a number of new challenges have arisen with respect to the law of the sea, especially as a result of human-driven climate change.

This chapter will first discuss the main subjects of international law and explain their principal features. Second, this chapter will zoom in on states, the traditional and principal actors in the international legal system. It will discuss the criteria for statehood under international law, the role that recognition plays in this respect, and explain how new states emerge. Finally, this chapter will turn to an analysis of the right to self-determination, a notion that plays an important role in the creation of states and is considered to be the most prominent right of one of the subjects of international law: peoples.

Each state enjoys full sovereignty over its territory and therefore has, in principle, full jurisdiction over events and persons within its territory. The term “jurisdiction” is often associated with the power of a court to hear a case, but judicial or adjudicative jurisdiction is just one of three manifestations of jurisdiction. The exercise of jurisdiction is also manifested in the authority of states to prescribe rules (legislative or prescriptive jurisdiction) and the power of states to enforce rules (enforcement jurisdiction). Although the power of states to exercise jurisdiction follows from the principle of sovereignty, this power is not unlimited. Each state has to respect the personality and sovereign equality of other states, and overstepping this boundary entails a violation of public international law. This limitation is most pertinent when a state exercises jurisdiction outside its own territory, for example when it enforces domestic legislation outside of its territory or when it extends the application of its domestic laws to people, property, or events outside its own territory. This chapter discusses the scope of the jurisdiction of states when states exercise enforcement, prescriptive, and adjudicative jurisdiction in relation to persons, property, and acts outside their own territory.

This chapter begins by explaining why international lawyers typically begin discussions about the sources of public international law by referencing Article 38 of the Statute of the International Court of Justice (ICJ). It then introduces treaties and custom, which are the two main sources of law in this field, before discussing other sources, namely general principles of law, decisions of international organizations, unilateral declarations, as well as judicial decisions and the teachings of international legal experts. The chapter ends with a discussion of non-binding instruments, which do not contain binding legal rules, but are nonetheless significant in the international legal field, as they contain norms that impact the behavior of states.

International law on immunities consists of a body of procedural rules that limit when a state may exercise jurisdiction within its territory. These procedural rules could prevent a domestic court from exercising jurisdiction in a case involving a foreign state, a foreign state official, or an international organization. These rules could also prevent a police officer from exercising jurisdiction by arresting and detaining a foreign diplomat or a minister of foreign affairs. International law bars the exercise of jurisdiction in such situations, either because the exercise of jurisdiction would threaten the equality of sovereign states or because the capacity of the individual or organization to carry out their functions would be compromised. This chapter begins with the law on state immunity, which has evolved over the centuries from an absolute doctrine to a more restrictive one, which permits exceptions, in particular when states engage in commercial activities. The chapter introduces the immunities that apply to all individuals who serve as state officials, whether they serve as relatively low-level civil servants or as the president or prime minister. The chapter also deals with two special regimes, one governing diplomatic and consular agents who serve abroad, and the other governing international organizations.

IHL has historically been divided into two main branches, consisting of rules that regulate the “means and methods of warfare”and the rules that deal with the “protection of persons and projects.” The rules governing the means and methods of warfare are known as “Hague Law” due to the fact that the main treaties governing this field of law were, for a long time, the 1899 and 1907 Hague Conventions and the annexed Hague Regulations. The provisions dealing with the protection of persons and objects hors de combat (“out of combat”) are known as “Geneva Law,” as these rules can be found in the Four Geneva Conventions of 1949. The two Additional Protocols of 1997 cover both norms concerning the means and methods of warfare, and those protecting individuals. This chapter begins with the foundations and the history of IHL, before discussing the scope of application of IHL and the law governing the conduct of hostilities, namely the means and methods of warfare. The final sections discuss the law governing the protection of persons during armed conflict, and the implementation and enforcement of IHL.

This chapter begins by elaborating on the concept of a dispute, before providing a historical perspective on the evolution of the requirement to settle disputes peacefully. The chapter then explores diplomatic as well as legal methods of dispute settlement. Diplomatic forms of dispute settlement (also known as political or non-legal forms of dispute settlement) include negotiation, mediation, inquiry, and conciliation. Legal forms of dispute settlement include arbitration and adjudication. Resort by states to dispute settlement procedures, and in particular legal methods of dispute settlement, has grown exponentially in the last decades. Since the 1990s, the International Court of Justice has had an increasingly active docket of cases, and, in addition, the Permanent Court of Arbitration has undergone a sort of renaissance. The focus of this chapter will be on the settlement of inter-state disputes, as opposed to disputes between states and non-state actors or between non-state actors.

This chapter explores international law relating to the protection of the environment, a relatively new field of international law that covers a broad range of concerns. The pollution of the oceans and the seas, the extinction of animal species, deforestation, and climate change: these are all concerns addressed by international environmental law. This chapter begins by providing a brief overview of the evolution of international environmental law and explains the principal characteristics of this field of international law. It further considers the interrelationship with the concept of sustainable development, which is central to modern approaches toward protecting the environment. It then explores two of the principal concerns addressed by international environmental law: first, the conservation of flora and fauna; and, second, the prevention of pollution and related environmental harm. Furthermore, the chapter discusses compliance and enforcement mechanisms. Lastly, because environmental protection measures often have implications for international trade, it briefly deals with the interrelationship between international environmental law and trade law.

This chapter introduces the jus ad bellum: the rules of law determining when states may resort to war or, more broadly, the use of armed force. These rules must be distinguished from the jus in bello: these are the rules of law that apply in armed conflict (known as international humanitarian law). In order to put the current jus ad bellum rules into perspective, the chapter begins by introducing the concept of collective security and demonstrating how this was applied during the League of Nations era. The following sections set out the relevant rules of the UN Charter on the prevention and regulation of recourse to the use of force, with a particular focus on the prohibition on the threat or use of force. The chapter also discusses the collective use of force, meaning the use of force authorized by the Security Council, and the unilateral use of force in self-defense. Finally, the chapter examines whether new exceptions to the prohibition of the use of force are emerging -- in particular, humanitarian intervention and the responsibility to protect.

This chapter will first discuss the main subjects of international law and explain their principal features. Second, this chapter will zoom in on states, the traditional and principal actors in the international legal system. It will discuss the criteria for statehood under international law, the role that recognition plays in this respect, and explain how new states emerge. Finally, this chapter will turn to an analysis of the right to self-determination, a notion that plays an important role in the creation of states and is considered to be the most prominent right of one of the subjects of international law: peoples.

This chapter begins by explaining why international lawyers typically begin discussions about the sources of public international law by referencing Article 38 of the Statute of the International Court of Justice (ICJ). It then introduces treaties and custom, which are the two main sources of law in this field, before discussing other sources, namely general principles of law, decisions of international organizations, unilateral declarations, as well as judicial decisions and the teachings of international legal experts. The chapter ends with a discussion of non-binding instruments, which do not contain binding legal rules, but are nonetheless significant in the international legal field, as they contain norms that impact the behavior of states.