The tenacity of this article is to provide a short-lived introduction to the sources of international law. It examines treaty, custom, and general principles of law and the subsidiary sources of judicial decisions and the thoughts of the most highly capable promoters. Furthermore, it reports the question of whether the list of sources in the Statute of the International Court of Justice is comprehensive and varnishes by considering possible ladders between sources.
People started living in states so they started entering into formal relationships with one another. Over the centuries, the development of traditions is based on how such relationships are directed.
Traditions make up ‘international law’. A wide range of subjects such as security, safety, diplomatic and political relations, trade, culture, and human rights by international law, but it varies from the domestic legal system in several necessary ways.
There is no such enforcing legislature or institution in international law. Consequently, international law is based on self-enforcement by the states which gave the consent. The consent can be expressed in various ways in terms of deriving the rules of international law. One obvious way is an explicit treaty that can impose obligations on the states. Except for treaties, other documents and agreements are serving as guidelines for the conduct of states, however, they are not binding.
Formal and Material Sources 
As pointed out by Starke,” The material sources of international law may be defined as the actual materials from which an international lawyer determines the rule applicable to a given situation.”
“The term ‘source’ refers to methods of the procedure by which international law is created.” There is a difference between formal and material sources. As pointed out by G. Fitzmaurice, They may be called as respectively;
- Direct and indirect
- Proximate or immediate
- Remote and ultimate
The core of division, therefore, the thing which motivates the content of the law, and the thing which provides that the content its compulsory character as law “The former are those legal procedures and methods for the creation of rules of general application which are legally binding on the addressee. The material sources provide evidence of the existence of rules which, when proved, have the status of legally binding rules of general application.” Further, “The sources of international law, this is to be found on the other hand, concerning the particular rules which constitute the system, and the processes by which he becomes identifiable as rules of law. The sources of the rules of law, while therefore distinct from the basis of the law, are nevertheless necessarily related to the basis of the legal system as a whole.” The sources of international law are many. The states commit to sources to different degrees of international law.
- Article 38 of the statue of the International Court of Justice is commonly documented as a certain statement of the sources of international law.
- According to article 38 of the statue of the court of justice, there are five categories to define sources of international law; – 
- International conventions
- International customs;
- General Principles of Law Recognized by Civilized Nations;
- Decisions of Judicial or Arbitral Tribunals and Juristic works;
- Decisions or Determinations of the Organs of the International Institutions.
The credible source of International Law is International Conventions. The term ‘convention or treaty’ is used for all types of international agreements which are known by a variety of different names such as convention, pact, declaration, protocol as well as the name agreement itself. A treaty or convention is defined as an international agreement entered between states in written form and governed by international law.
Treaties are two kinds of-
- Lawmaking treaty-entered by a large number of states
- Treaty contract-entered by two or more states
The treaties are imposed on the states that are legally binding and they impose obligations on the states about how they treat all the individuals within their jurisdiction. Majorly, International Conventions protect human rights have been adopted.
Article 38(b) of the statute of the International Court of Justice identifies ‘International Customs, as evidence of general practice accepted as law’ as one of the sources of international law.
International customs are the primary source of international law. Custom is a habit that has been repeated for a long time and acquires the force of law. Usage of the earlier stage of development of customs. Where usage ends customs starts. It is only in the modern period that the importance of customs has suffered a setback. However, even today it is regarded as one of the important sources of international law. Customary rules of international law are the rules which have been developed in a long process of historical development.
To understand the usage of the meaning of ‘custom’, it is necessary to know the meaning of the word ‘usage’. The words ‘custom’ and ‘usage’ are often used as synonymous. There is a difference between the usage of custom and usage, and they are not synonyms. Usage may be inconsistent and opposed to each other. But this can never be the case with custom. When states in their international relations start behaving in a particular way in certain circumstances, it is expected that in similar circumstances they will behave in the same way. This is called usage. But when this usage receives the general acceptance of recognition by the states in their relations with each other there develops the conception of obligation that becomes custom.
Customary International Law is much more mutual law in international law than in most native legal systems. This reproduces the incapacity of international law to grow an efficient process of writing law creation.
General Principles of Law Recognized by Civilized Nations
All the nations are now considered civilized Nations. This is the third primary source of international law if the first two primary sources are not available then these rules are applied.
General Principals of law a source of international law that is hypothetically correspondent treaty or custom laws. But General Principals are used to closing gaps left by treaty and customary laws in actual practice. These Principals are established by comparing the national legal system.
Especially, international arbitral tribunals often apply the general principle of laws and they are quite useful also. All the domestic legal systems cannot be compared by anybody so it becomes complicated too. General Principals of law plays an important role in case-laws regarding human rights.
Does one question arise that why are general principles used? None of the legislation can deliver answers to every query and to every possible condition which arises. Hence, rules of law or principles that enable decision-makers and supporters of the executive and judicial divisions to choose on the issues before they are needed. General principles of law performances two vital roles: on the one hand, they deliver strategies for judges, in particular, in deciding in separate cases; on the other hand, they edge the unrestricted power of judges and supporters of the executive in their judgments in separate cases.
Decisions of Judicial or Arbitral Tribunals and Juristic works
Judicial decisions and decisions of Arbitral tribunal are also sources of international law but it is treated as a subsidiary source of international law. Since the doctrine of precedent does not apply in the field of international law, international judicial decisions are generally not binding.
International Judicial Decisions, – The main international judicial tribunal is the International Court of Justice. It was situated as a successor of the Parliament Court of International Justice. Hence, it may be noted that the decision which is given by the International Court of Justice does not generate a mandatory common rule of international law. Article 59 of the statute of the International Court of Law defines that there will not have any binding force of the decision of the court expect between the parties and the particular case of decisions of the court. Earlier, the decision of the court was not obligatory on the courts because the courts have the right to deviate from its judgment or decision. However, Courts do not deviate from its decision, it changes in very unusual situations.
Juristic works are writings of the legal Scholars. This is the option of jurists in the field of international law. Juristic works are also treated as a subsidiary source of international law.
Decisions or Determinations of the Organs of the International Institutions.
Decisions or Determinations of the Organs of the International Institutions also play an important role in the development of international law. However, Article 38 did not at all mentioned decisions and determinations of the organs of the international institutions as a source of international law because international organizations did not play such an important role as they have done now.
The reason for this omission is easily explained. The official list of the statute of the International Court of Justice was drafted 80 years ago. Therefore, international organizations are a prominent feature of international law.
Some decisions contain generally binding rules, like the regulation of the European Community, and are comparable to domestic legislation. Many others, like the resolutions of the United Nations, are normally just recommendations. But it does not follow legally irrelevant. The recommendations frequently rely on legal arguments.
The tenacity of these general comments or recommendations is to help the state parties in fulfilling their responsibilities.
There are different foundations of international law as conventions/treaties, customary international law, and general principles of law. In their definite application, however, these sources are faithfully interconnected. They often cooperate by accompanying and switching each other. Often a rule made in one type of source later appears in the form of another source. Thus, these distinctive sources of international law should never be noticed in seclusion.
The law-making course in the present international system is far from supreme, it is poorly harmonized and rather disorganized. Bearing in mind, this structural softness, the system works amazingly well most of the time. However, this should not encourage satisfaction. The nature and the enormousness of present and potential global tasks necessitate fresh thinking in the scope of international law. It will require imagination to come up with innovative ideas and systems and much courage to instrument them successfully.
Frequently Asked Questions
- What are the sources of international human rights law?
- What are Article 38 ICJ?
- Are International Judicial Decisions legally binding?
- J.G. Starke, Introduction to International Law, Tenth Edition (Butterworth, 1989), Starke’s International Law, Eleventh, Edition, Butterworths (September 1994) p, 28
- Edward Collins, International Law in a Changing World (1969), p.16.
- Lan Brown line, Principles of Public International Law, Second Edition (Clarendon Press Oxford, 1973), p. 1.
- Oppenheim’s International Law, Ninth Edition, Longman Group UK Limited, and Mrs. Tomoko Hudson, 1992, p. 23.
- See the judgment of the International Court of Justice in Nicaragua vs United States ICJ reports (1986) 15 et seq.
- International Law & Human Rights, DR. S.K. KAPOOR, Central Law Agency
- Oppenheim’s International Law, Ninth Edition, Longman Group UK Limited, and Mrs. Tomoko Hudson, 1992, p. 23.