Sources of international law are the origins or foundations from which legal rules and principles in the international legal system are derived. These sources help determine the content, scope, and application of international law.
The primary sources of international law are recognized in Article 38(1) of the Statute of the International Court of Justice (ICJ), which is often considered a key reference for identifying these sources.
Primary Sources of International Law
Treaties
- Treaties, also known as conventions, accords, pacts, or agreements, are formal, written agreements between two or more sovereign states or international organizations.
- Treaties are a fundamental source of international law and create legally binding obligations for the parties involved.
- Examples include bilateral agreements, multilateral treaties, and international conventions like the United Nations Charter.
Customary International Law
- Customary international law arises from established state practices (state practice) that are followed because states believe they are legally required (opinio juris).
- Customary law develops over time through consistent and widespread state practice and is considered legally binding even in the absence of a formal treaty.
- An example is the customary prohibition against the use of force in international relations, except in self-defense or with authorization from the United Nations Security Council.
General Principles of Law
- General principles of law recognized by civilized nations serve as a source of international law.
- These principles include concepts of justice and fairness that are common to many legal systems and can be applied when there is a gap in international treaties or customary law.
- They provide a foundation for resolving disputes and making legal decisions in international law.
Judicial Decisions and Legal Scholarship
- Decisions of international courts and tribunals, such as judgments of the International Court of Justice (ICJ) and decisions of other specialized international courts, can help clarify and develop international legal principles.
- Legal writings and scholarship by experts and jurists in the field of international law contribute to the interpretation and development of international legal norms.
Subsidiary Means for the Determination of Rules of Law
- This category, mentioned in Article 38(1) of the ICJ Statute, encompasses additional sources that may be used to ascertain international law when primary sources do not provide a clear answer.
- Subsidiary means can include the teachings of eminent jurists, decisions of national courts, and the practice of international organizations.
