Public International Law

Public international law, also known as the Law of Nations, is a set of norms aimed at regulating the interaction between the subjects of international law that participate in international relations. Public international law norms create a common framework within which the subjects of international law operate and contribute to the existence of generally stable, organized, and consistent international relations.

While public international law governs the relationship between the subjects of international law, such as States, private international law addresses the private law rights of natural or legal persons. Private international law consists of a set of conflicts of laws rules applicable in international cases. These rules determine the applicability of a certain law in circumstances involving a choice between the municipal law of different States.

Public international law applies to the subjects of international law, such as States and international organizations, who consent to be governed by it. While the traditional doctrine of international law did not regard individuals as subjects of international law, a more contemporary approach dictates that the individual is indeed a subject of international law and the owner of rights and obligations in the international arena (in particular in areas such as international human rights law, international criminal law, and international humanitarian law). However, it should be noted that, subject to certain Resolutions by the United Nations Security Council, there is no generally accepted coercive authority that can bind sovereign States to a body of international law.

Public international law is important because it governs the behavior of the several subjects of international law, including States. Public international law reinforces the principle of sovereign equality among all States. It also lends predictability and order to the relationship between the subjects of international law. It also, arguably, constrains the behavior of the subjects of international law such as States, preventing them from engaging in a course of conduct incompatible with their international obligations, which might lead to international censure, economic retaliation, or military action.

Article 38 of the Statute of the International Court of Justice refers to three sources of international law under the traditional theory of sources: treaties, customary international law, and general principles of law. That same provision also refers to two subsidiary means for the determination of the rules of law: judicial decisions and the teachings of highly qualified publicists.

The Vienna Convention on the Law of Treaties is a treaty that addresses the conclusion in writing of international treaties governed by international law between States. It sets forth guidelines for the negotiation and conclusion of such treaties. It also addresses, among other topics, the provisional application of treaties, their interpretation and application, reservations, and the causes for their suspension and/or termination. The procedures for the conclusion of treaties have both internal and external aspects. External procedures include the negotiation of the text of the treaty, the adoption of the final text, its authentication, and the expression of consent to be bound by the treaty (by signature, exchange of instruments constituting a treaty, ratification, acceptance or approval, or accession). The internal procedures vary between States, and may involve legislative approval, ratification by the Executive Branch and publication in the Official Gazette.

Customary international law is one of the sources of international law. Article 38 of the Statute of the International Court of Justice refers to customary international law as “evidence of a general practice accepted as law.” Its elements are State practice and the States’ subjective conviction that a certain form of conduct is required by international law, known as opinio juris.

Subject to certain Resolutions by the United Nations Security Council, which can approve peacekeeping missions, impose sanctions, or authorize the use of force when said Council determines there is a threat to international peace and security, there is no generally accepted coercive authority that can bind sovereign States to a body of international law. International laws are, generally, enforced by consent. In other words, States comply with their international law obligations because they choose to do so, not because there is a coercive entity that requires their adherence to the law. Failures to abide by public international law norms are often met with ad hoc responses that range from diplomatic responses, to measures ordered by the Security Council entailing economic action and military force.

According to the traditional doctrine of international law, only some of the several actors in the international scene, such as States and international organizations, are subjects of international law (entities capable of possessing international rights and obligations) and possess international legal personality. The traditional doctrine also recognizes atypical subjects of international law, which includes the Holy See, the Sovereign Order of Malta, and the International Committee of the Red Cross. Other entities such as non-self-governing peoples, insurgents, and movements of national liberation have also been considered by part of the doctrine as subjects of international law. A more contemporary approach dictates that the individual is also subject of international law and the owner of rights and obligations in the international arena (in particular in areas such as international human rights law, international criminal law, and international humanitarian law). The status of indigenous peoples and multinational enterprises as subjects of international law is also under discussion.