Understanding the Sources of International Law: A Comprehensive Guide
Sources of International Law: A Comprehensive Guide
1. Introduction
International law is a set of rules governing relations between states. It primarily consists of rules recognized by states in their interactions and often arises from international customs and treaties. Article 38 of the Statute of the International Court of Justice serves as an authoritative text on the sources and evidence of international law.
2. Definitions of International Law
Oppenheim: “International law is a body of customary and conventional rules considered binding on civilized states in their relations with each other.”
Starke: “It is a body of customary and conventional rules considered binding on civilized states in their relations with each other and includes the functioning of international institutions and their relations with each other and states, as well as individuals in relation to states and international institutions.”
3. Sources of International Law
While there is no international legislature or court to which the international community must compulsorily submit, Article 38 of the Statute of the International Court of Justice outlines where rules of international law can be found, such as international conventions and international customs.
4. Meaning of Sources
Starke: “By sources of international law, we mean the actual materials from which an international lawyer ascertains the rule applicable to a given situation.”
5. Classification of Sources
Sources of international law can be categorized into two groups:
- Formal sources
- Material sources
I. Formal Sources of International Law
A formal source is where a rule of law derives its force and validity. International law lacks formal sources, and one of the main criticisms against it is the absence of its own legislature, leading to a lack of sanction for its laws.
II. Material Sources of International Law
Material sources of international law are the actual materials from which an international lawyer determines the rule applicable to a specific situation. Article 38 of the Statute of the International Court of Justice lists these material sources, encompassing both primary and secondary sources. Part two of Article 38 specifically enumerates secondary sources.
7. Main Sources of International Law
I. Primary Sources
(i) International Customs
International customs are among the most important sources of international law, recognized as such by Article 38 of the Statute of the International Court of Justice.
Essentials of a Valid International Custom:
- Long duration
- Uniformity and consistency (Asylum Case, 1950: “The rule invoked should be in accordance with a constant and uniform usage practiced by the states in question.”)
- Generality of practice or observance
- Opinio juris et necessitates
(ii) Treaties
Treaties are a crucial source of international law.
Definition of Treaty:
Article 2 of the Vienna Convention on the Law of Treaties (1960) defines a treaty as: “An agreement whereby two or more states establish or seek to establish a relationship between them governed by international law.”
Kinds of Treaties:
- Law-making Treaties: Provisions of law-making treaties directly serve as a source of international law. They function similarly to legislation in the state field, enabling the adaptation of international law to changing times and circumstances and strengthening the rule of law among states.
- Treaty Contracts: Treaty contracts are agreements between two or more states, with provisions binding on the parties involved. They serve as an indirect source of international law.
(iii) General Principles of Law
General principles of law recognized by civilized states are another important source of international law. These principles are rules acknowledged by most states.
Case Law:
Chorzow Factory Case (1927): In this case, the Permanent Court of International Justice applied the general principle of Res Judicata.
General Principles Recognized by International Courts:
International courts have recognized various principles in different decisions, including:
- Good faith
- Responsibility
- Prescription
- Right of a court to determine its own jurisdiction
- Impartiality of judges and arbitrators
- Res judicata
- Estoppel
- Audi alteram partem (right to be heard)
(iv) Judicial Decisions
While juristic works serve as evidence of international law, they gain significance in the absence of established customs or treaties.
Lawrence’s Views: “A writer on international law, in a sense, himself legislates, for he creates the opinion that is really supreme.”
(v) Decisions and Determinations of International Institutions
Decisions on jurisdictional matters by organs of international institutions can have a law-making effect. Sometimes, these organs are authorized to provide binding determinations regarding the interpretation of their constituent instruments.
(vi) State Papers
State papers, excluding treaties, also contribute to international law. The archives of foreign affairs departments in various countries contain valuable expert opinions relevant to international law.
II. Secondary Sources
Secondary sources of international law include:
- State judicial decisions
- International comity
- Equity and natural justice
- Jus cogens
- State practices
- Private contracts
- Roman law
- Principles of Islamic law
8. Subjects of International Law
Subjects of international law encompass:
- States
- Political entities legally proximate to states
- Condominiums
- International territories
- International organizations
- International institutions
- International criminal law
- Treaties concerning international minorities and individuals
- Non-state entities
- Insurgents
9. Conclusion
Sources of international law represent the historical foundation from which rules of conduct emerge. Despite the absence of a compulsory international legislature or court, Article 38 of the Statute of the International Court of Justice provides a framework for identifying and understanding these sources.