public international law

Definition of public international law

Further reading

Public international law concerns the structure and conduct of sovereign states; analogous entities, such as the Holy See; and intergovernmental organizations. To a lesser degree, international law also may affect multinational corporations and individuals, an impact increasingly evolving beyond domestic legal interpretation and enforcement. Public international law has increased in use and importance vastly over the twentieth century, due to the increase in global trade, environmental deterioration on a worldwide scale, awareness of human rights violations, rapid and vast increases in international transportation and a boom in global communications.

The field of study combines two main branches: the law of nations (jus gentium) and international agreements and conventions (jus inter gentes), which have different theoretical foundations and should not be confused.

Public international law should not be confused with "private international law", which is concerned with the resolution of conflict of laws. In its most general sense, international law "consists of rules and principles of general application dealing with the conduct of states and of intergovernmental organizations and with their relations inter se, as well as with some of their relations with persons, whether natural or juridical."

"It is probably the case that almost all nations observe almost all principles of international law and almost all of their obligations almost all the time."
-Louis Henkin

Sources and scope

Public international law has three principal sources: international treaties, custom, and general principles of law. In addition, judicial decisions and teachings may be applied as "subsidiary means for the determination of rules of law" (cf. Art. 38 of the Statute of the International Court of Justice). International treaty law comprises obligations states expressly and voluntarily accept between themselves in treaties. Customary international law is derived from the consistent practice of States accompanied by opinio juris, i.e. the conviction of States that the consistent practice is required by a legal obligation. Judgments of international tribunals as well as scholarly works have traditionally been looked to as persuasive sources for custom in addition to direct evidence of state behavior (and they are also explicitly mentioned as such in Art. 38 of the Statute of the International Court of Justice, as subsidiary means for the determination of rules of law). Attempts to codify customary international law picked up momentum after the Second World War with the formation of the International Law Commission (ILC), under the aegis of the United Nations. Codified customary law is made the binding interpretation of the underlying custom by agreement through treaty. For states not party to such treaties, the work of the ILC may still be accepted as custom applying to those states. General principles of law are those commonly recognized by the major legal systems of the world. Certain norms of international law achieve the binding force of peremptory norms (jus cogens) as to include all states with no permissible derogations.

Public international law establishes the framework and the criteria for identifying states as the principal actors in the international legal system. As the existence of a state presupposes control and jurisdiction over territory, international law deals with the acquisition of territory, state immunity and the legal responsibility of states in their conduct with each other. International law is similarly concerned with the treatment of individuals within state boundaries. There is thus a comprehensive regime dealing with group rights, the treatment of aliens, the rights of refugees, international crimes, nationality problems, and human rights generally. It further includes the important functions of the maintenance of international peace and security, arms control, the pacific settlement of disputes and the regulation of the use of force in international relations. Even when the law is not able to stop the outbreak of war, it has developed principles to govern the conduct of hostilities and the treatment of prisoners. International law is also used to govern issues relating to the global environment, the global commons such as international waters and outer space, global communications, and world trade.

Whilst municipal law is hierarchical or vertical in its structure (meaning that a legislature enacts binding legislation), international law is horizontal in nature. This means that all states are sovereign and theoretically equal. As a result of the notion of sovereignty, the value and authority of international law is dependent upon the voluntary participation of states in its formulation, observance, and enforcement. Although there may be exceptions, it is thought by many international academics that most states enter into legal commitments with other states out of enlightened self-interest rather than adherence to a body of law that is higher than their own. As D. W. Greig notes, "international law cannot exist in isolation from the political factors operating in the sphere of international relations".

Breaches of international law raise difficult questions for lawyers. Since international law has no established compulsory judicial system for the settlement of disputes or a coercive penal system, it is not as straightforward as managing breaches within a domestic legal system. However, there are means by which breaches are brought to the attention of the international community and some means for resolution. For example, there are judicial or quasi-judicial tribunals in international law in certain areas such as trade and human rights. The formation of the United Nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the Security Council.

Traditionally, sovereign states and the Holy See were the sole subjects of international law. With the proliferation of international organizations over the last century, they have in some cases been recognized as relevant parties as well. Recent interpretations of international human rights law, international humanitarian law, and international trade law (e.g., North American Free Trade Agreement (NAFTA) Chapter 11 actions) have been inclusive of corporations, and even of certain individuals.

Branches of public international law

• Consular law
• Diplomatic law
• International aviation law
• International criminal law
• International environmental law
• International human rights law
• International humanitarian law
• International space law
• International trade law
• Law of state responsibility
• Rule according to higher law
• United Nations Convention on the Law of the Sea
• Use of force continuum
• Use of force