International Law

1. International Law: A Framework for Global Order

Law is that element which binds the members of the community together in their adherence to recognised values and standards.

Order over Chaos. International law provides a framework of principles and rules that regulate the behavior of states, international organizations, and, in some cases, individuals. It aims to establish order and stability in the international system, preventing chaos and promoting a just existence.

Permissive and Coercive. Like domestic law, international law is both permissive and coercive. It allows states to establish legal relations with rights and duties, such as through treaties, and it punishes those who violate its regulations, although enforcement mechanisms differ significantly from domestic systems.

Distinct from Comity and Morality. It's important to distinguish international law from international comity (courtesy practices) and international morality (ethics). While international law is a legal discipline with specific content and form, comity is based on courtesy, and morality is a branch of ethics.

2. The Evolution of International Law: From Ancient Times to Today

In the quarter-century since this book first appeared, there have been few moments of uncertainty as to the direction of international relations and international law to compare with the early years of the twenty-first century.

Ancient Roots. While modern international law emerged with the rise of European nation-states, its roots can be traced back to ancient civilizations. Early treaties, such as the one between Lagash and Umma (c. 2100 BC) and the treaty between Rameses II and the Hittite king, demonstrate the existence of international agreements and principles.

European Development. The development of international law was heavily influenced by European notions of sovereignty, the rise of the nation-state, and the rediscovery of Greco-Roman ideas during the Renaissance. The Reformation and the subsequent religious wars further shaped the need for a system of rules to govern relations between states.

Modern Transformations. The 20th and 21st centuries have witnessed significant shifts in international relations, including globalization, the rise of international terrorism, and increasing human rights violations. These events have challenged traditional conceptions of international behavior and necessitated the attention given to international law and the notion of international legitimacy.

3. Sources of International Law: Custom, Treaties, and Principles

The fourth edition that appeared in 1997 has been extensively revised.

Article 38 of the ICJ Statute. The primary sources of international law are outlined in Article 38 of the Statute of the International Court of Justice:

• International conventions (treaties)
• International custom
• General principles of law recognized by civilized nations
• Judicial decisions and the teachings of the most highly qualified publicists (as subsidiary means)

Customary International Law. Customary law arises from the consistent practice of states, coupled with opinio juris, the belief that such practice is legally binding. It can evolve over time through state actions and reactions, shaping the legal landscape.

Treaties and General Principles. Treaties are express agreements between states, creating binding obligations for the signatories. General principles of law, derived from municipal legal systems, fill gaps in international law and provide a basis for legal reasoning.

4. The Interplay of International and Municipal Law

Increasing resort to force by states, entities and individuals coupled with the apparently easy access to weapons of high destructive capacity pose a significant challenge to those wishing to establish a world order based on justice, mutual respect, toleration and forbearance.

Dualism vs. Monism. The relationship between international law and municipal law is a subject of debate. Dualism posits that international and municipal law are separate systems, while monism views them as part of a unified legal order.

Municipal Law in International Law. A state cannot justify a breach of international law by invoking its municipal law. International law prevails over conflicting domestic rules.

International Law in Municipal Courts. States adopt different approaches to incorporating international law into their domestic legal systems. Some states automatically incorporate customary international law, while others require specific legislative action. Treaties generally require legislative implementation to have effect within municipal courts.

5. Subjects of International Law: States and Beyond

In the quarter-century since this book first appeared, there have been few moments of uncertainty as to the direction of international relations and international law to compare with the early years of the twenty-first century.

States as Primary Subjects. Traditionally, states have been the primary subjects of international law, possessing rights and duties enforceable at the international level. However, the scope of international law has expanded to include other entities.

Expanding Legal Personality. International organizations, individuals, and, to a limited extent, non-governmental organizations (NGOs) and transnational corporations (TNCs) have gained recognition as subjects of international law, with specific rights and responsibilities.

Self-Determination and Individuals. The principle of self-determination has empowered peoples to determine their political status, while the development of international human rights law has granted individuals certain rights and protections under international law.

6. Human Rights: A Core Element of Modern International Law

Increasing human rights violations committed in the Kosovo province of Yugoslavia in 1998–9 precipitated an air attack by NATO undertaken not in self-defence nor pursuant to a United Nations mandate but rather on explicit humanitarian grounds.

The Rise of Human Rights. The international protection of human rights has become a central concern of international law, with numerous treaties and institutions dedicated to promoting and enforcing human rights standards.

Universal vs. Relative. The debate between universalism and cultural relativism highlights the tension between the idea that human rights are inherent and applicable to all people versus the view that human rights are culturally specific and should be interpreted within the context of particular societies.

Implementation Mechanisms. The United Nations system includes various mechanisms for implementing human rights, such as the Commission on Human Rights, treaty-based committees, and special rapporteurs. These bodies monitor state compliance, investigate human rights violations, and provide recommendations for improvement.

7. Regional Human Rights Systems: Europe, the Americas, and Beyond

Certain key events must be noted, for they have combined to shift the orientation of international relations.

Regional Protection. Regional human rights systems, such as the European Convention on Human Rights, the American Convention on Human Rights, and the African Charter on Human and Peoples' Rights, provide additional layers of protection and enforcement.

European Convention System. The European Convention on Human Rights, with its Court of Human Rights, has been particularly influential, establishing a robust system for individual complaints and judicial review.

Other Regional Systems. The American Convention and the African Charter offer similar protections, although their implementation mechanisms and effectiveness vary.

8. Recognition: Acknowledging States and Governments

One important consequence of the increasing instability of international relations has been the attention given to international law and the notion of international legitimacy.

Recognition of States vs. Governments. Recognition of states is distinct from recognition of governments. Recognition of a state acknowledges its existence as a legal person under international law, while recognition of a government acknowledges its authority to represent the state.

Theories of Recognition. The constitutive theory posits that recognition creates statehood, while the declaratory theory argues that recognition merely acknowledges an existing factual situation.

Effects of Recognition. Recognition has significant legal effects, both internationally and within municipal legal systems. Recognized states and governments can exercise rights and duties under international law, including the right to sue in foreign courts and claim immunity from jurisdiction.

9. Territory: The Foundation of State Sovereignty

To mark the increasing significance of inter-state courts and tribunals, former materials have been updated, rewritten and gathered into a new chapter, while the previous section on international humanitarian law has been expanded to constitute a separate chapter.

Territory as a Core Concept. Territory is a fundamental element of statehood, providing the basis for sovereignty and jurisdiction. International law governs the acquisition, transfer, and control of territory.

Modes of Acquiring Territory. Traditional modes of acquiring territory include occupation, prescription, cession, accretion, and conquest. However, the use of force to acquire territory is now generally prohibited under international law.

Territorial Disputes. Territorial disputes often arise from conflicting claims, historical ties, and the principle of self-determination. International law provides mechanisms for resolving such disputes, including negotiation, arbitration, and judicial settlement.

10. Air Law and Space Law

Globalisation has brought undoubted benefits in the fields of commerce, technology and communications, but also increased dangers concerning the rapid spread of disease and the growth of international terrorism.

Air Law. Air law governs the use of airspace, including the rights and responsibilities of states regarding air navigation, air safety, and liability for damages caused by aircraft.

Space Law. Space law regulates activities in outer space, including the exploration and use of space, the status of celestial bodies, and liability for damages caused by space objects.

Key Principles. Both air law and space law are based on principles of state sovereignty, freedom of navigation, and international cooperation.

11. The Law of the Sea

The clearly understood rules and limitations as to state conduct apparent during the Cold War period have disappeared and (for the moment at least) the optimism engendered by a renewed United Nations in the early 1990s has dissipated.

Maritime Zones. The law of the sea establishes different maritime zones, including internal waters, the territorial sea, the contiguous zone, the exclusive economic zone (EEZ), and the continental shelf, each with varying degrees of coastal state jurisdiction.

Rights and Duties. Coastal states have specific rights and duties within each maritime zone, including the right to regulate navigation, fishing, and resource exploitation, as well as the duty to protect the marine environment.

High Seas. The high seas are open to all states, with freedoms of navigation, overflight, fishing, and scientific research. However, these freedoms are subject to limitations, such as the duty to prevent pollution and the suppression of piracy.

12. Jurisdiction

The fourth edition that appeared in 1997 has been extensively revised.

Defining Jurisdiction. Jurisdiction is the power of a state to prescribe, adjudicate, and enforce rules within its territory and beyond. It is a fundamental aspect of state sovereignty.

Principles of Jurisdiction. Key principles of jurisdiction include the territorial principle (based on the location of the act), the nationality principle (based on the nationality of the perpetrator), the passive personality principle (based on the nationality of the victim), the protective principle (based on the security interests of the state), and the universality principle (based on the nature of the crime).

Immunities from Jurisdiction. States and their representatives enjoy certain immunities from the jurisdiction of foreign courts, including sovereign immunity and diplomatic immunity. These immunities are designed to protect state sovereignty and facilitate international relations.

13. Immunities from Jurisdiction

To mark the increasing significance of inter-state courts and tribunals, former materials have been updated, rewritten and gathered into a new chapter, while the previous section on international humanitarian law has been expanded to constitute a separate chapter.

Sovereign Immunity. States are generally immune from the jurisdiction of foreign courts, although this immunity is subject to exceptions, such as commercial activities.

Diplomatic Immunity. Diplomatic agents enjoy extensive privileges and immunities, including inviolability of person and premises, immunity from criminal and civil jurisdiction, and exemption from taxes and customs duties.

Purpose of Immunities. These immunities are designed to protect state sovereignty and facilitate effective diplomatic relations.

14. State Responsibility

All the other chapters have been re-examined, updated and often rewritten.

Breach of International Obligation. State responsibility arises when a state breaches an international obligation, whether arising from treaty, custom, or general principles of law.

Attribution. The act or omission must be attributable to the state, meaning it was committed by a state organ or by individuals acting on behalf of the state.

Consequences of Responsibility. The consequences of state responsibility include cessation of the wrongful act, reparation for the injury caused, and the possibility of countermeasures by the injured state.

15. International Environmental Law

In addition, a short list of what are seen as the most important publications has been added after each chapter in order to assist those wishing to take their studies further and a section on useful websites has been added (see p. 1216).

State Responsibility and the Environment. States have a duty to prevent transboundary environmental harm and are responsible for damage caused by activities within their jurisdiction or control.

International Cooperation. International environmental law emphasizes cooperation among states to address global environmental challenges, such as atmospheric pollution, ozone depletion, and marine pollution.

Key Principles. Key principles of international environmental law include the precautionary principle, the polluter-pays principle, and the principle of sustainable development.

16. The Law of Treaties

I have also been able to correct some errors.

Treaty Formation. The law of treaties governs the making, interpretation, and termination of international agreements. Treaties are a primary source of international law.

Validity and Termination. Treaties may be invalidated due to coercion, fraud, or conflict with jus cogens norms. They may be terminated or suspended due to material breach, supervening impossibility, or fundamental change of circumstances.

Interpretation. Treaty interpretation is guided by principles of good faith, ordinary meaning, context, and object and purpose.

17. State Succession

I would like particularly to thank Finola O’Sullivan of Cambridge University Press for her encouragement, assistance and above all patience.

Continuity and Succession. State succession addresses the legal consequences of changes in statehood, such as the creation of new states, mergers, or dissolutions.

Succession to Treaties. Succession to treaties depends on the type of treaty and the nature of the succession. Territorial treaties generally continue, while political treaties do not.

Other Matters. Succession also affects membership of international organizations, state property, archives, and debts.

18. The Settlement of Disputes by Peaceful Means

Particular gratitude is owed to Diane Ilott for her careful and thorough copy-editing and to Chantal Hamill and Mauren MacGlaslon for so carefully preparing the index and tables respectively.

Diplomatic Methods. Diplomatic methods of dispute settlement include negotiation, good offices, mediation, inquiry, and conciliation. These methods rely on communication and persuasion to reach a mutually acceptable resolution.

International Institutions. International institutions, such as the United Nations and regional organizations, play a role in dispute settlement by providing forums for negotiation, offering good offices, and establishing commissions of inquiry or conciliation.

Arbitration. Arbitration involves the submission of a dispute to a neutral third party for a binding decision. It is a more formal and legalistic method of dispute settlement than diplomatic procedures.

19. Inter-State Courts and Tribunals

A debt remains to Sir Elihu Lauterpacht QC for his encouragement in the development of this work.

Judicial Settlement. Judicial settlement involves the submission of a dispute to a permanent court, such as the International Court of Justice (ICJ), for a binding decision based on international law.

The International Court of Justice. The ICJ is the principal judicial organ of the United Nations and has jurisdiction to hear disputes between states and to provide advisory opinions on legal questions.

Proliferation of Courts. The proliferation of international courts and tribunals has led to concerns about fragmentation and inconsistency in international law.

20. International Law and the Use of Force by States

I also remain grateful to my many colleagues from many countries for their advice and encouragement, while reassuring them that all responsibility for the end product rests squarely with me.

The UN Charter. The UN Charter prohibits the threat or use of force in international relations, except in cases of self-defense or when authorized by the Security Council.

Self-Defense. The right of self-defense is an inherent right of states under customary international law and Article 51 of the UN Charter. It is limited by principles of necessity and proportionality.

Intervention. Intervention in the internal affairs of another state is generally prohibited, except in certain limited circumstances, such as humanitarian intervention.

21. International Humanitarian Law

As ever, the real and deepest thanks are due to my wife Judith and my children, Talia, Ilan and Daniella.

Development. International humanitarian law (IHL), also known as the law of armed conflict, seeks to minimize human suffering in times of war. It has developed from the Geneva Conventions and the Hague Conventions.

Scope of Protection. IHL protects persons not taking part in hostilities, such as civilians, prisoners of war, and the wounded and sick. It also regulates the conduct of hostilities, prohibiting certain weapons and tactics.

Enforcement. Enforcement of IHL is challenging, but mechanisms include war crimes tribunals and the principle of universal jurisdiction.

Last updated: March 11, 2025