The Statute of the International Court of Justice (ICJ)
The sources of international law can be found in Article 38.1 of the Statute.
This portfolio of sources was extracted from Article 38 of the original world court's constitutive statute.
Article 38 (1) of the Statute of the International Court of Justice is generally recognized as a definitive statement of the sources of international law. It requires the Court to apply, among other things, (a) international conventions, whether general or particular, establishing rules expressly recognized by the contesting states; (b) international custom, as evidence of a general practice accepted as law; (c) the general principles of law recognized by civilized nations; (d) subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.
Historic considerations and development
During the 19th century, it was recognized by legal positivists that a sovereign could limit its authority to act by consenting to an agreement according to the principle pacta sunt servanda. This consensual view of international law was reflected in the 1920 Statute of the Permanent Court of International Justice, and was later preserved in Article 38(1) of the 1946 Statute of the International Court of Justice.
On the question of preference between sources of international law, rules established by treaty will take preference if such an instrument exists. It is also argued however that international treaties and international custom are sources of international law of equal validity; this is that new custom may supersede older treaties and new treaties may override older custom. Also, jus cogens (peremptory norm) is a custom, not a treaty. Certainly, judicial decisions and juristic writings are regarded as auxiliary sources of international law, whereas it is unclear whether the general principles of law recognized by 'civilized nations' should be recognized as a principal or auxiliary source of international law. Nevertheless, treaty, custom, and general principles of law are generally recognized as primary sources of international law.
Treaties as law
Main article: Treaties
Treaties and conventions are the persuasive source of international law and are considered "hard law." Treaties can play the role of contracts between two or more parties, such as an extradition treaty or a defense pact. Treaties can also be legislation to regulate a particular aspect of international relations or form the constitutions of international organizations. Whether or not all treaties can be regarded as sources of law, they are sources of obligation for the parties to them. Article 38(1)(a) of the ICJ, which uses the term "international conventions", concentrates upon treaties as a source of contractual obligation but also acknowledges the possibility of a state expressly accepting the obligations of a treaty to which it is not formally a party.
For a treaty-based rule to be a source of law, rather than simply a source of obligation, it must either be capable of affecting non-parties or have consequences for parties more extensive than those specifically imposed by the treaty itself.
Thus, the procedures or methods by treaties become legally binding are formal source of law which is a process by a legal rule comes into existence: it is law creating.
Treaties as custom
Some treaties are the result of codifying existing customary law, such as laws governing the global commons, and jus ad bellum. While the purpose is to establish a code of general application, its effectiveness depends upon the number of states that ratify or accede to the particular convention. Relatively few such instruments have a sufficient number of parties to be regarded as international law in their own right. The most obvious example is the 1949 Geneva Conventions for the Protection of War Victims.
Most multi-lateral treaties fall short of achieving such a near universal degree of formal acceptance and are dependent upon their provisions being regarded as representing customary international law and, by this indirect route, as binding upon non-parties. This outcome is possible in a number of ways:
- When the treaty rule reproduces an existing rule of customary law, the rule will be clarified in terms of the treaty provision. A notable example is the Vienna Convention on the Law of Treaties 1969, which was considered by the ICJ to be law even before it had been brought into force.
- When a customary rule is in the process of development, its incorporation in a multilateral treaty may have the effect of consolidating or crystallizing the law in the form of that rule. It is not always easy to identify when this occurs. Where the practice is less developed, the treaty provision may not be enough to crystallize the rule as part of customary international law.
- Even if the rule is new, the drafting of the treaty provision may be the impetus for its adoption in the practice of states, and it is the subsequent acceptance of the rule by states that renders it effective as part of customary law. If a broad definition is adopted of state practice, the making of a treaty would fall within the definition. Alternatively, it is possible to regard the treaty as the final act of state practice required to establish the rule in question, or as the necessary articulation of the rule to give it the opinion juries of customary international law.
- Convention-based "instant custom" has been identified by the ICJ on several occasions as representing customary law without explanation of whether the provision in question was supported by state practice. This has happened with respect to a number of provisions of the Vienna Convention on the Law of Treaties 1969. If "instant custom" is valid as law, it could deny to third parties the normal consequences of non-accession to the
The United Nations Charter
Pursuant to Chapter XVI, Article 103 of the United Nations Charter, the obligations under the United Nations Charter overrides the terms of any other treaty. Meanwhile, its Preamble affirms establishment of the obligations out of treaties and source of international law.
Main article: Customary international law
Article 38(1)(b) of the ICJ Statute refers to "international custom" as a source of international law, specifically emphasizing the two requirements of state practice plus acceptance of the practice as obligatory or opinio juries save necessitatis (usually abbreviated as opinion juries).
Derived from the consistent practice of (originally) Western states accompanied by opinion juries (the conviction of States that the consistent practice is required by a legal obligation), customary international law is differentiated from acts of comity by the presence of opinion juries (although in some instances, acts of comity have developed into customary international law, i.e. diplomatic immunity). Treaties have gradually displaced much customary international law. This development is similar to the replacement of customary or common law by codified law in municipal legal settings, but customary international law continues to play a significant role in international law.
When examining state practice to determine relevant rules of international law, it is necessary to take into account every activity of the organs and officials of states that relate to that purpose. There has been continuing debate over where a distinction should be drawn as to the weight that should be attributed to what states do, rather than what they say represents the law. In its most extreme form, this would involve rejecting what states say as practice and relegating it to the status of evidence of opinion juries. A more moderate version would evaluate what a state says by reference to the occasion on which the statement was made. It is only relatively powerful countries with extensive international contacts and interests that have regular opportunities of contributing by deed to the practice of international law. The principal means of contribution to state practice for the majority of states will be at meetings of international organizations, particularly the UN General Assembly, by voting and otherwise express their view on matters under consideration. Moreover, there are circumstances in which what states say may be the only evidence of their view as to what conduct is required in a particular situation.
The notion of practice establishing a customary rule implies that the practice is followed regularly, or that such state practice must be "common, consistent and concordant". Given the size of the international community, the practice does not have to encompass all states or be completely uniform. There has to be a sufficient degree of participation, especially on the part of states whose interests are likely to be most affected, and an absence of substantial dissent. There have been a number of occasions on which the ICJ has rejected claims that a customary rule existed because of a lack of consistency in the practice brought to its attention.
Within the context of a specific dispute, however, it is not necessary to establish the generality of practice. A rule may apply if a state has accepted the rule as applicable to it individually, or because the two states belong to a group of states between which the rule applies.
A dissenting state is entitled to deny the opposability of a rule in question if it can demonstrate its persistent objection to that rule, either as a member of a regional group or by virtue of its membership of the international community. It is not easy for a single state to maintain its dissent. Also, rules of the jus cogens have a universal character and apply to all states, irrespective of their wishes.
Demand for rules that are responsive to increasingly rapid changes has led to the suggestion that there can be, in appropriate circumstances, such a concept as "instant custom". Even within traditional doctrine, the ICJ has recognized that passage of a short period of time is not necessarily a bar to the formation of a new rule. Because of this, the question is sometimes raised as to whether the word "custom" is suitable to a process that could occur with great rapidity.
Practice by international organizations
It may be argued that the practice of international organizations, most notably that of the United Nations, as it appears in the resolutions of the Security Council and the General Assembly, are an additional source of international law, even though it is not mentioned as such in Article 38(1) of the 1946 Statute of the International Court of Justice. Article 38(1) is closely based on the corresponding provision of the 1920 Statute of the Permanent Court of International Justice, thus predating the role that international organizations have come to play in the international plane. That is, the provision of Article 38(1) may be regarded as 'dated, and this can most vividly be seen in the mention made of 'civilized nations', a mentioning that appears all the more quaint after the decolonization process that took place in the early 1960s and the participation of nearly all nations of the world in the United Nations.
A wealth of state practice does not usually carry with it a presumption that opinio juris exists. “Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is rendered obligatory by the existence of a rule of law requiring it.”
In cases where practice (of which evidence is given) comprises abstentions from acting, consistency of conduct might not establish the existence of a rule of customary international law. The fact that no nuclear weapons have been used since 1945, for example, does not render their use illegal on the basis of a customary obligation because the necessary opinion juries was lacking.
Although the ICJ has frequently referred to opinion juries as being an equal footing with state practice, the role of the psychological element in the creation of customary law is uncertain.
A peremptory norm or jus cogens (Latin for "compelling law" or "strong law") is a principle of international law considered so fundamental that it overrides all other sources of international law, including even the Charter of the United Nations. The principle of jus cogens is enshrined in Article 53 of the Vienna Convention on the Law of Treaties:
- For the purposes of the present Convention, a peremptory norm of general international law is a norm accepted and recognised by the international community of States as a whole as a norm from which no derogation is permitted and which can be modified only by a subsequent norm of general international law having the same character.
Rules of jus cogens generally require or forbid the state to do particular acts or respect certain rights. However, some define criminal offenses which the state must enforce against individuals. Generally included on lists of such norms are prohibitions of such crimes and internationally wrongful acts as waging aggressive war, war crimes, crimes against humanity, piracy, genocide, apartheid, slavery and torture.
The evidence supporting the emergence of a rule of jus cogens will be essentially similar to that required to establish the creation of a new rule of customary international law. Indeed, jus cogens could be thought of as a special principle of custom with a superadded opinions juries. The European Court of Human Rights has stressed the international public policy aspect of the jus cogens.
General principles of law
The scope of general principles of law, to which Article 38(1) of the Statute of the ICJ refers, is unclear and controversial but may include such legal principles that are common to a large number of systems of municipal law. Given the limits of treaties or custom as sources of international law, Article 38(1) may be looked upon as a directive to the Court to fill any gap in the law and prevent a nonliquet by reference to the general principles.
In earlier stages of the development of international law, rules were frequently drawn from municipal law. In the 19th century, legal positivists rejected the idea that international law could come from any source that did not involve state will or consent but were prepared to allow for the application of general principles of law, provided that they had in some way been accepted by states as part of the legal order. Thus Article 38(1)(c), for example, speaks of general principles "recognized" by states. An area that demonstrates the adoption of municipal approaches is the law applied to the relationship between international officials and their employing organizations, although today the principles are regarded as established international law.
The significance of general principles has undoubtedly been lessened by the increased intensity of treaty and institutional relations between states. Nevertheless, the concepts of estoppel and equity have been employed in the adjudication of international disputes. For example, a state that has, by its conduct, encouraged another state to believe in the existence of a certain legal or factual situation, and to rely on that belief, may be estopped from asserting a contrary situation in its dealings. The principle of good faith was said by the ICJ to be "[o]ne of the basic principles governing the creation and performance of legal obligations". Similarly, there have been frequent references to equity. It is generally agreed that equity cannot be employed to subvert legal rules (that is, operate contra legem). This "equity as law" perception is reinforced by references to equitable principles in the text of the United Nations Convention on the Law of the Sea 1982, though this may be little more than an admission as to the existence, and legitimation, of the discretion of the adjudicator.
However, the principles of estoppel and equity in the international context do not retain all the connotations they do under common law. The reference to the principles as "general" signify that, if rules were to be adapted from municipal law, they should be at a sufficient level of generality to encompass similar rules existing in many municipal systems. Principles of municipal law should be regarded as sources of inspiration rather than as sources of rules of direct application.
Judicial decisions and juristic writings
According to Article 38(1)(d) of its Statute, the ICJ is also to apply "judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law". It is difficult to tell what influence these materials have on the development of the law. Pleadings in cases before the ICJ are often replete with references to case law and to legal literature.
The decisions of international and municipal courts and the publications of academics can be referred to, not as a source of law as such, but as a means of recognizing the law established in other sources. In practice, the International Court of Justice does not refer to domestic decisions although it does invoke its previous case-law.
There is no rule of stare decisis in international law. The decision of the Court has no binding force except between the parties and in respect of that particular case. Nevertheless, often the Court would refer to its past decisions and advisory opinions to support its explanation of a present case.
Often the International Court of Justice will consider General Assembly resolutions as indicative of customary international law.
Article 38(1)(d) of the International Court of Justice Statute states that the 'teachings of the most highly qualified publicists of the various nations' are also among the 'subsidiary means for the determination of the rules of law'. The scholarly works of prominent jurists are not sources of international law but are essential in developing the rules that are sourced in treaties, custom and the general principles of law. This is accepted practice in the interpretation of international law and was utilized by the United States Supreme Court in The Paquete Habana case (175 US (1900) 677 at 700-1).
- ^What are the Sources of international law?, Available at Learning the Law. Also see Definition of international law
- ^"Statute of the Court". International Court of Justice, United Nations. Retrieved 18 September 2016.
- ^Solmanson, William (2011). Fundamental Perspectives on International Law. Boston: WADSWORTH CENGAGE Learning. p. 27. ISBN 978-0-495-79723-4.
- ^Statute of the International Court of Justice.
- ^Martin Dixon, Textbook on International Law (Oxford University Press, 7th ed 2013) 24
- ^Legal Consequences for States of the Continued Presence of South Africa in Namibia (South-West Africa) notwithstanding Security Council Resolution 276 (1970) (Advisory Opinion)  ICJ Reports 16 at 47.
- ^North Sea Continental Shelf cases, note 6 at 38.
- ^North Sea Continental Shelf cases, note 6 at 41. See also Trial of the Major War Criminals before the International Military Tribunal, Vol. 1, Judgment, 171 at 253–4.
- ^D'Amato, A., The Concept of Custom in International Law (Cornell University Press: Ithaca, New York, 1971) at 88.
- ^Thirlway, H., International Customary Law and its Codification (A. W. Sijthoff: Leiden, 1972) at 58.
- ^See Case Concerning Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) (Merits)  ICJ Reports 14.
- ^Fisheries Jurisdiction Case (United Kingdom v Iceland) (Merits)  ICJ Reports 3 at 50.
- ^North Sea Continental Shelf Cases (Federal Republic of Germany v Denmark; Federal Republic of Germany v Netherlands)  ICJ Reports 4 at 42.
- ^Nicaragua case (Merits), note 4 at 98.
- ^Asylum Case (Colombia v Peru)  ICJ Rep 266 at 277; Advisory Opinion on the Legality of the Threat or Use by a State of Nuclear Weapons in Armed Conflict  ICJ Reports 226.
- ^Case Concerning Right of Passage over Indian Territory (Portugal v India) (Merits)  ICJ Reports 6 at 39; Asylum case, note 8 at 276.
- ^North Sea Continental Shelf cases, note 6 at 229, 232 per Judge Lachs.
- ^Asylum case, note 8 at 277–8.
- ^Fisheries Case (United Kingdom v Norway) (Judgment)  ICJ Reports 116, at 131.
- ^See North Sea Continental Shelf cases, note 6 at 229 per Judge Lachs.
- ^North Sea Continental Shelf cases, note 6 at 43.
- ^See North Sea Continental Shelf cases, note 6 at 44.
- ^Legality of Nuclear Weapons Advisory Opinion (GA), note 8.
- ^Case Concerning the Continental Shelf (Libyan Arab Jamahiriya v Malta) (Judgment)  ICJ Reports 13 at 29; Legality of Nuclear Weapons Advisory Opinion (GA), note 8 at 16.
- ^1155 UNTS 331.
- ^Amerasinghe, C., The Law of the International Civil Service, 2nd rev. ed, vol. 1 (Clarendon Press: Oxford, 1994) at 151–8.
- ^See North Sea Continental Shelf cases, note 6 at 26; Flegenheimer Claim 25 ILR 91; Case Concerning the Temple of Preah Vihear (Cambodia v Thailand) (Merits)  ICJ Reports 6 at 32–3.
- ^Nuclear Tests Cases (Australia v France; New Zealand v France)  ICJ Reports 253 at 268.
- ^River Meuse Case (Netherlands v Belgium) PCIJ Reports Series A/B No 70 76 at 76 per Judge Hudson.
- ^Case Concerning the Frontier Dispute (Burkina Faso v Republic of Mali) (Judgment)  ICJ Reports 554 at 567–8; North Sea Continental Shelf cases, note 6 at 46–50.
- ^International Status of South-West Africa (Advisory Opinion)  ICJ Reports 128 at 148.
- ^Article 59 of the ICJ StatuteStatute of the International Court of Justice.
- Thirlway, H., International Customary Law and its Codification (A. W. Sijthoff: Leiden, 1972).
A nineteenth century postulate of positivism suggested that a sovereign could limit his authority to act by consenting to an agreement (as per the principle of pacta sunt servanda) and that treaties bind only those privy to them (as per the principle of pacta tertiis nec nosunt, nec prosunt). This positivist, consensual view of international law remains preserved in Article 38 of the 1946 Statute of the International Court of Justice (ICJ), which is the definitive statement on the sources of international law. This article will discuss the relevance of Article 38 today and highlight some of its weaknesses and points for improvement.
According to Article 38, the ICJ is required to apply, among other things, international conventions (that are expressly recognized by the contesting states), international custom, (as evidence of a general practice accepted as law), general principles of law, judicial decisions, and juristic writings as means for the determination of rules of law.Clause 2 of the Article speaks of the settlement of disputes ex aequo et bono (meaning ‘in keeping with equity and good conscience’) and without prejudice to the power of the Court.
There has been much discussion about Article 38’s standing and its treatment of the conceptual scope and framework of the sources of international law. The Article’s aim is to determine exactly what the ICJ may deem to be international law and what it may apply when deciding disputes or giving advisory opinions. Consequently, scholars, lawyers, and others involved with international law have been looking into the four sources of law that Article 38 enumerates: international conventions, international custom, the general principles of law, and judicial decisions and the teachings of the ‘most highly qualified publicists’.
So where does Article 38 stand today? In terms of its use in the real world, the Article has been a ready guide for those wanting to determine the sources of international law, to gauge the pulse of the law. Aside from this, the article has not been subjected to interpretation by the ICJ or debate in international fora, so as to suggest its overhauling. If we look at the core principles and the wording of Article 38, we can see that it is fraught with redundant information and irregularities, and needs to be reviewed. The reasons for this are plenty and are considered below.
First and foremost, the hierarchical arrangement of the sources themselves is fallacious. Although Article 38 lists the primary sources, it is in fact not based on lex specialis derogat generali (meaning ‘a law governing a specific subject matter overrides a law that only governs general matters’) and hence it should not have a hierarchy. However, practice and scholarly usage suggests otherwise. To understand the futility of the hierarchical arrangement, one needs to read Article 53 of the Vienna Convention on the Law of Treaties. This Article indicates that the norms of international law are accepted and recognized by the international community as a whole and there can be no derogation whatsoever from them. The fact that peremptory norms are prevalent in both customary and treaty law means that neither type of law can be typified as being ‘superior’ or ‘above’ the other. Besides, the ICJ is not the only international dispute resolution body; there are plenty of tribunals, arbitration-based organizations, and courts. With so many international dispute resolution bodies, it is parochial to think that the ICJ has the last word on the question of sources.
Second, Article 38 restricts the evolution and applicability of legal principles to states. It ignores other entities that qualify as subjects of international law. The foundation stone of international law is the protection of sovereignty and the equality of states. The Statute of the ICJ was drafted with the world order at the end of the Second World War in mind. International law at that juncture presumed that states were the only subjects of the law. A slew of human rights conventions, regional treaties governing regional alliances, and conventions addressing violent non-state actors (such as terrorists) all suggest the induction of non-state entities as subjects of international law. Article 38 continues to presuppose that international law deals with states alone. It ignores all non-state actors, which have evolved as subjects of international law today.
Third, the Article emphasizes a consent-based legal system that hinges upon voluntary action. In reality, states are often bound by norms that they have not explicitly consented to. In theory, states are bound to follow only those norms that they consent to, whether by signing a treaty or by believing that a custom binds them. Additionally, several commonly followed practices are grouped under the heading of ‘general principles of law’. In reality, states are actively bound by norms that they have not quite consented to. Several jus cogens obligations (those obligations that are of a peremptory nature, from which no derogation shall be permitted) and even erga omnes obligations (those obligations that bind everyone, irrespective of their consent to being bound) have not really been consented to, but nevertheless bind all states. For example, the Security Council, pursuing its mandate under Chapter VII of the United Nations (UN) Charter, passes resolutions with a fifteen-state body that bind other states even though they have not consented to the same. Therefore, the consent-based legal system cannot be the only basis for international law.
Fourth, Article 38 is incomplete in many respects. Conspicuously absent are the role of the resolutions of the UN General Assembly and the Security Council and an enumeration of what constitutes customary international law and general state practice. In reality, states are bound by jus cogens and erga omnes obligations, but nothing in the statutory matrix explains the importance of these principles. The Article is also silent on persistent objectors (states that object to a usage before it becomes a custom), subsequent objectors (states that object to a customary practice after the usage has evolved into a custom), and their role in the evolution of customary international law. It makes no mention of opinio juris (the principle that a state follows a custom because it believes itself bound to follow it); it does not speak of how many states must follow a practice in order for it to be considered a custom; nor does it say how one may determine the existence of a customary practice itself. The role of regional customary practice is also excluded. The consequent complications are plenty, since states bear the burden of proving that they are either bound or not bound by a specific custom or practice.
Fifth, much of the redundancy in Article 38 comes from the language of the provision itself. Using the phrase ‘civilized nations’, Article 38 is still couched in the terminology of the post-war period, where the ideological supremacy and the superior status assumed by some states marked the legal mindset of the UN’s founding fathers. Today, the Article should speak of ‘states’ and not qualify them as ‘civilized’ or ‘uncivilized’, for there really is no longer a true hierarchy of states. When the Statute of the ICJ was drafted, the five founding members of the UN assumed a higher position in comparison to the rest of the world, most of which was just becoming states after decolonization. Much of this ‘higher’ status is growing irrelevant today, with talk of expanding the permanent membership of the Security Council and dismantling the veto power that its five permanent members currently hold.
Finally, the importance that the Article attaches to the “teachings of the most highly qualified publicists of various nations” and to customary and state practice has less relevance in a world comprising nearly 200 states and counting. When the Statute was drafted, there were about 40 nation-states that made up the international anarchical system and relying on scholarly opinion was a feasible practice. Today, that feasibility is lost in the burgeoning number and varied practices of states. Many of these teachings are actually intellectual writings and often have political overtones. In all fairness, one cannot call these ‘sources of law’, since each author professes a viewpoint quite distinct from the next. If these teachings were construed to be sources of law within the ambit of Article 38, given the number of texts that exist today, there would hardly be any law—the contradictions in viewpoints alone would be enough to confuse anyone.
International law cannot afford to be watered down. Starting at the top, there are so many questions as to what the law itself is, and what the true source is of something that has come to be law. True, the international branch of law has come to be known as soft law, but one cannot turn a blind eye to the areas that scream for improvement and that can, in fact, be improved. The sources of law are fraught with irregularities and questions still remain. Although Article 38 has helped define international law as a discipline distinct from politics and international relations, it has fallen short of seeing the process through. As dynamic as society is, law needs to be one step ahead to ensure that there is a means to keep actions and omissions in check. Therefore, reviewing Article 38 would bode well for the evolution of international law.
Kirthi Jayakumar is a member of the e-IR editorial team, and a graduate from the School of Excellence in Law, Chennai. She also volunteers with the United Nations and writes for several publications, including Femina.
 M. Mendelson, The International Court of Justice and the Sources of International Law, in V.Lowe/M.Fitzmaurice (eds.), Fifty Years of the International Court of Justice, 1996, 63-89
 Charles De Visscher: De l’equite dans le reglement arbitral ou judicaire des litiges de droit international public, Paris 1972, pp.17-26