Tanya Agarwal, 3rd Year Ba. LLB (Hons), Amity Law School, Delhi (GGSIPU). The following article explains the origin and sources of International Law through various places from which it evolved along with its application in states and international organisations.


International Law is comprehensive in nature and due to that it is an amalgamation of various sources, there exists no single system of laws which can interpret and extend the law but international law still exists and is ascertainable.

There are ‘sources’ available from which the rules of international law may be extracted and analyzed. According to Lawrence, if we take the source of law which has all the authority required to give it binding force, then in respect of International Law there is one source of law and that is the consent of Nations. This consent may be either tacit (custom) or express (treaties).

Major sources which form the conventional source of International law includes the International Convention and Treaties. Sources of International Law can be bifurcated into primary and secondary sources which are explained below.

Primary Sources

Primary Sources of International Law are considered formal in nature. They come from official bodies which include Treaties, Customs and principle of Law. Article 38(1)(a-c) of the ICJ statute is widely recognized as the backbone of the formal source of International Law. It is generally regarded as an authoritative statement of the sources of international law. Article 38 of the Statute of the International Court of Justice in The Hague has been treated as a convenient catalogue of international legal sources.

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Article 38 of the ICJ statute:

Article 38(1)(a-c) of the ICJ was adopted by the same provision of the statute of the Permanent Court of International Justice which operated under the auspices/support of Legal of Nations in 1920. The article refers to the primary sources of international law which are enumerated below:

Custom as a Source of International Law

The original and the oldest sources Law is known as Custom. The rules of customary International Law involved a long historical process which gained recognition by the entire community. The presence of customary rules can be deduced from state practice and behaviour because it is not a written source of law. A rule of customary law is said to have two elements:

First, there must be widespread and consistent State practice.

Secondly, there has to be “opinio Juris”, a Latin term which means a legal obligation to believe in the existence of such law.

Features of Customary Law

Uniform and general

State practice to give rise to binding rules of customary International Law, that practice must be uniform, consistent and general and must be coupled with a belief that the practice is obligatory rather than habitual. In the Asylum Case, the court declared that a customary rule must be used constantly and uniformly throughout history which can be traced through state practice.


Continuous and regular use of particular conduct is considered as a rule of customary law. In the North Sea Continental Shelf cases, the ICJ stated that there is no precise length of time during which the practice must exist. It is simply that it must be followed long enough to show that other requirements of custom are satisfactory.

An opinion of Law.

To assume the status of customary international law the rule in question must be regarded by the state as binding in Law i.e. the states must regard themselves as being under a legal obligation to follow the practice. In the Lotus case,opinio Juris was seen as an essential element of customary international law and this was affirmed in North Sea Continental Shelf Cases as well.

Convention as a source of International Law

Treaties and conventions are one of the most important sources of International Law. These conventions can be multilateral or bilateral. Multilateral conventions relate to the treaties which formulate the universal or general application of the law. On the other hand, bilateral conventions are those which is formed exclusively by two states to deal with a particular matter concerning these states.

Vienna Convention on the Law of Treaty 1969, the codified law for contracting treaties, gives the definition, “A treaty is an agreement whereby two or more states establish or seek to establish a relationship between them governed by international law.” Treaties act as a direct source of rights and obligations for the states, they codify the existing customary source of law.

They are voluntary and cannot bind non-signatory to it, however, there are certain exceptions to it that is if any rule forms part of the Jus Cogens norm as they are part of the accepted principles of International law and every state has a peremptory duty of not breaching them due to their erga omnes obligations. (owed to the whole world)

General Principle of International Law

Most modern jurists accept general principles of law as common to all national legal systems, in so far as they are applicable to the relations of States. There are fewer decided cases in international law than in a municipal system and no method of legislating to provide rules to govern new situations. It is for such a reason that the provision of ‘the general principles of law recognized by civilized nations’ and was inserted into article 38 as a source of law.

Some of the examples of General principles include:

  • The rule of res judicata which has been affirmed by the court in the case of Genocide Convention Bosnia and Herzegovina v. Serbia and Montenegro,
  • The rules of pacta sunt servanda made applicable,
  • Reparation must be made for damage caused by the fault, 
  • The right of self-defence for the individual against attack on his person, family, or community against a clear and present danger,
  • For one’s own cause no one can be a judge and that the judge must hear both sides.

Secondary source (Evidence of International law)

Article 38(1)(d) forms part of the material source of International Law also known as the secondary source. It states that judicial decisions and the teachings of the most highly qualified publicists of the various nations also help in guiding the formation of international law, however they are not binding but merely advisory in nature. 

Judicial Decision

Under this, the court is authorised to apply previous decisions of the court which are also known as an evidence of international law, however, it is subject to the exception stated under Article 59 of the statute which states that the previous decision of the court can only guide the court, it is not binding on the court.

This article provides the court with a rule that it is not to be bounded by precedents but recourse can still be made by the court to its past decision’s res judicata and advisory opinion to substantiate current case as authoritative evidence of legal position.

ICJ plays a major role in the law-making process through its advisory opinions, case laws and judge’s rule. One of the major examples of this includes the principle of the prohibition against the use or threat of use of force laid down by the court in the case of Nicaragua vs. USA which is now considered as a part of Customary International Law. T

he judicial decision of the court also encompasses international arbitral awards and the rulings of national courts. One leading example is Alabama Claims arbitration, which marked the opening of a new era in the peaceful settlement of international disputes, in which increasing use was made of judicial and arbitration methods in resolving conflict.

Another illustration of the impact of arbitral awards is the Island of Palmas case wherein it has been referred that a unanimous, or nearly unanimous, decision plays an important role in the progressive development of the law. It helps in providing a single view for interpretation of the issue at hand which helps in avoiding controversy during the development of International Law.

Juristic writings and teachings

Other major parts of this source also include the ‘teachings of the highly qualified writers such as Gentili, Grotius, and Vattel who were considered as the supreme authorities of the international law in the 16th to 18th Centuries.

Textbooks are used as a method of discovering what the law is on any particular point rather than as the source of actual rules, and the writings of even the most respected international lawyers cannot create law. These are considered as an evidentiary source of law as they provide an explanation and understanding of the International principles. They carry an essential value because they provide to fill the grey areas of International Law where treaties or customs do not exist.

Other sources of International Law

International law is not based on a set of rules and therefore article 38 is not exhaustive. There are various other factors that develop the usage of International Law which include declarations of Security Council resolutions, declarations, and recommendations adopted by the UN General Assembly, International morality and equity, etc.

The world is constantly evolving and the problems are becoming more complex, the resolutions and declarations adopted by assembly act as an inevitable impact upon the direction adopted by modern international law. The way states vote in the General Assembly and the explanations given upon such occasions constitute evidence of state practice and state understanding as to the law.

For example, in the case of the USA vs Nicaragua, General Assembly had asked the court for an advisory opinion on the question: “is the threat or use of Nuclear weapons in any circumstances permitted under International Law?” The court after a review of the relevant international legal instrument as well as the Security Councils’ General Assembly resolution of the matters reached a resolution that the threat or use of nuclear weapons would generally be contrary to the rules of International Law applicable to armed conflicts and in particular the principles and rules of humanitarian law.

The concept of equity has been referred to in several cases. In the Rann of Kutch Arbitration between India and Pakistan in 1968, the Tribunal agreed that equity formed part of international law and that accordingly, the parties could rely on such principles in the presentation of their cases.

UN has provided a true compliment for the gap created in what is supposed to be an accurate reflection of other sources of international law and its activities has positively affected lawmaking ways by resolutions and faster means by 15 members of the Security Council and 191 members of the General Assembly as greater needs arise for fast development of international law codified by International law commission.

States and International Organisation

International Law is a system of rights and duties given to a legal system so that they can exercise them at a global level. There are different International bodies that are subject to possession of such rights under customary law and therefore also have the privilege for bringing any claim if there is a violation of their rights.

The determination of the personality of these bodies depends mainly upon the nature and extent of particular rights and duties. With the evolution of International law, it is necessary to determine the inter-relationship between these bodies and their capacity to enforce claims as per their rights and duties. These bodies may include states, international organizations, regional organizations, non-governmental organizations, and individuals.


States have international legal personality to the fullest extent. They constitute one of the most important international organizations as they form the primary centre for the collection of the social activities of civilization.

The doctrine of Recognition – Creation of Statehood

Recognition of the state is an International Concept wherein a new state or an existing state is given a formal acknowledgement of being a member of the International community. According to Article 1 of the Montevideo Convention on the Rights and Duties of States, 1933 and Oppenheim, the entity of a state can be created if it possesses the following characteristics:

  1. Defined Territory
  2. Population
  3. Government
  4. Capacity to enter into a relationship with another state

However, there is no set pattern recognized so far which forms a particular base for the recognition of statehood as per the above criteria. Such provisions are neither exhaustive nor immutable. Recognition of a statehood grants certain privileges in the form of rights, duties, and immunities which include the authority to enter into a foreign relation with another state, became a part of a treaty, the right to undergo succession and become a member of the United Nations. There are two theories on recognition which are:

Declaratory Theory

The theory was propounded by eminent jurists such as Fisher and Brierly, under this theory the independence of a new state does not take into account its acceptance by other states. The theory has been given in Article 3 of the Montevideo Convention where it recognizes the existence of a new state does not depend upon the mind of the existing state’s consent.

Consecutive Theory

Oppenheim proposed this theory wherein it stated that for a state to be considered as an International entity, it is necessary for it to be recognized by other sovereign states so that it can enjoy its rights and duties. The theory does not propose the non-existence of a state rather it places an emphasis on acceptance by other states for a state to enjoy their exclusive rights.

Recognition of a States

There are two modes of recognition of states which are as follows:




It is the Provisional and factual recognition of statehood

It is the legal recognition of statehood by existing states

It forms the primary step before de Jure Recognition of the state

It can be granted either with or without grant of de facto recognition

It is revocable, conditional or non-conditional in nature

It is non-revocable and non-conditional in nature

They cannot undergo state succession and therefore do not enjoy full diplomatic immunity

They can undergo state succession and therefore enjoy full diplomatic immunity

Its recognition is granted when there is the fulfilment of the essential conditions of statehood.

Its recognition is granted when the state fulfils all the essential condition of states along with sufficient control and permanency


When a state is recognized, there are two ways by which it can be declared which is:

Express Recognition

Expressed Recognition is done through an official notification or declaration by an existing state recognising the presence of a newly formed state. This category usually recognizes a de jure form of recognition unless provided otherwise by the recognizing state in the declaration for considering it under any other form.

Implied Recognition

The action of an existing act done impliedly which indicates acceptance to a new act as an International person is considered as a form of Implied Recognition. There can be several implied actions for instances speeches, declarations etc. It depends on a case-by-case basis.

Recognition of a government

The criteria laid down for recognition of a government is different from that of recognition of a state. In case of a newly formed government, it is necessary to check the constitutionality of the government to ensure a valid recognition of the same. When a new state comes into existence it becomes necessary to check the structure of the new government to ensure international standards are being followed.

Following criteria needs to be checked for recognizing a newly formed government:

  1. Sufficient control and power by the government over its population.
  2. The capacity of the new government to fulfil its international obligations and duties.

There are various theories which have been accepted for recognizing the government but the most prominent amongst them is the so-called doctrine of legitimacy, it was initially used by the United States in relation to Central America, but the theory declined gradually.

Recognition practice as per the USA

In the USA only a recognized state can sue, there are a line of legal precedents on the practice of recognition by the USA, for instance in the Salimoff case the terms of the certificate tended to encourage the court to regard the Soviet government as a recognized government, on the other hand, in the case of the Maret the tone of the executive’s statement on the Soviet Republic of Estonia was decidedly hostile to any notion of recognition or enforcement of its decrees.

In 1977, the United States declared that instead of focusing on the change in the government, they should try to establish the need for diplomatic relations and if the administration is willing to involve and conduct business with other governments.

Therefore, the US prefers to initiate diplomatic relations to recognize the government. It has been observed that the United States typically avoids taking the lead in recognition, waiting for the domestic politics to play out or for regional bodies like the Organization of American States to resolve the crisis before deciding whether to confer legitimacy on the new government. In the case of Honduras, for instance, the United States followed the lead of other Latin American countries in deeming Zelaya’s ouster illegitimate.

International Organization(IO)

Meaning and Nature

The International Community is an amalgamation of various voices and opinions, therefore with the growing need for international cooperation and to ensure peace in this community International Organization have emerged. An international organization has been defined as a form of co-operation of sovereign states based on multilateral international organizations and comprising of a relatively stable range of participants, the fundamental feature of which is the existence of permanent organs with definite competences and powers acting for the carrying out of common aims.

The essential elements which describe International organization include:

  1. Multilateral International agreement
  2. Individual Personality of the Institution
  3. Permanent organs carrying out its Function

International Organizations are usually created amongst states or by their duly authorized representatives, however, there is no uniform rule on the same, states sometimes create legal entity based on a treaty though are there to enforce and uphold the principles of a treaty such as European Court of Human Rights but they are not considered as International Organisations.

An international organisation may come into existence by the formation of a treaty or through an existing organisation granting certain powers for forming an international organisation. UNICEF is an International organisation which was formed by the United Nations General Assembly. 

Historical Development of International organisation

The development of IO can be traced from the need for establishing the psychological notion of world government. It was only in the 19th-century major IO’s emerged before that there were smaller councils like the Hanseatic League or the Swiss Confederation and the United Provinces of the Netherlands etc.

Embassies establishing bilateral needs were not sufficient and adequate to solve problems that arose between more than two states, there was a need to find a way so that interest of all the states can be represented so an International conference of all the representatives from several states was organized which came to be known as the principal originator IO namely Peace of Westphalia in 1648, which ended the thirty-year religious conflict of Central Europe and formally established the modern secular nation-state arrangement of European politics.

Till the first world war, the major issues were sought through conferences, for instance, in  1815 congress of Vienna marked the first systematic attempt to regulate international affairs by means of regular international conferences.

Due to several inconsistencies in the ad-hoc nature of these conferences, because they were only state-specific in nature and could only be called upon by the initiative of the interested states, international NGOs and public international unions like the International Committee of Red Cross and the inter-governmental associations emerged during the 19th Century for efficient functioning of vital arteries of communication such as the Rhine and Danube rivers.

With the continuous evolution of the society, it was noticed that an efficient body of IO can be established, and the League of Nations was the first international organization which was designed not just to organization operation between states in areas which some have referred to as ‘low politics’, such as transport and communication, or the more mundane aspects. However, after World War II, the league of the nation was disbanded due to its inefficiency and the United Nations was founded in 1919.


International law has emerged through various sources which have been codified in Article 38 of the ICJ statute which identifies customs, treaties and general principles as formal sources of International Law. However, the Judicial decision is given by the world court also acts as advisory opinions in guiding the development of International law.

Various philosophers and juristic theorists have enlightened the philosophy of  International law through their theories and principles as well. International Law helps in Identifying states as an entity of the world community through various modes so as to provide them with rights and duties. To ensure peace and order amongst the nation-states, International Organisation plays a major role in increasing cooperation and upholding the international law which has emerged from various sources.


  1. Bowett’s International Institutions, pp. 6–9.
  2. El Erian, ‘Legal Organization’, p. 58.
  5. 145 F.2d 431 (1944); 12 AD, p. 29. 
  6. The Sources of International Law’ (, October 2019) <> accessed 27 October 2019.
  7. Available at:
  8. Sources of International law In the light of Article 38 of the International Court of Justice By Shagufta Oma.
  9. The Sources of International Law’ (, October 2019) <> accessed 27 October 2019.
  10. Peter Malanczuk & Akehurst’s Modern Introduction to International Law, (London: George Allen & Unwin, 1997); 49.
  11. The additional clause relating to recognition by ‘civilised nations’ is regarded today as redundant: see e.g. Pellet, ‘Article 38’, p. 769.
  12.  Israr Khan, Article 38 of the Statute of the International Court of Justice: A Complete Reference Point for the Sources of International Law, THE NEW JURIST, 5th April 2019.

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