Article 38(1) of ICJ and sources of International Law

Critically discuss whether Article 38(1) of ICJ Statute exhaustively enumerates all sources of International Law.

Dipti Srivastava, Student of Law, Jindal Global Law School

Sources are the fundamental basis of International Law, which has the force of creating rights and obligations on the states concerned ((Malcom Evans (ed.), Hugh Thirlway, THE SOURCES OF INTERNATIONAL LAW, (2014), 91)). This paper attempts to answer a critical question discussing whether there are additional sources to International Law apart from those mentioned in the Article 38(1) of Permanent Court of International Justice (hereinafter referred as PCIJ). What are these sources and whether these additional sources have the force of being regarded as a formal source or not. This would ultimately contemplate that the sources given in the Article 38(1) of PCIJ is not exhaustive and there is need of the additional sources to gain recognition in the era of modern International Law.

What do we mean by ‘sources’? How is it different from domestic legal system?

Ascertainment of law in the international legal system is fairly ambiguous when compared to domestic legal order. Within International law, there is a lack of legislature, executive and a structure of courts ((6 Malcolm N. Shaw, INTERNATIONAL LAW, Cambridge, 70)). There is no single body able to create laws internationally binding on everyone, nor a proper system of courts with comprehensive and compulsory jurisdiction to interpret and extend the law ((ibid)). Therefore, there is a problem faced in discovering where the law is to be found and whether a particular proposition amounts to a legal rule ((ibid)). This primarily means that there is uncertainty regarding the emergence of the rules of International law, i.e. ‘sources’ of International law. This perplexity is reinforced because of the anarchic nature of world affairs and the clash of competing sovereignties ((Supra n. 2)). Nevertheless, international law does exist and is ascertainable in Article 38 (1) of ICJ, which is considered to be ‘sources’ of International Law. The debatable question which arises here is – Are these sources exhaustive or can it be argued that its merely descriptive?

Article 38 (1) of ICJ provides that the courts whose function is to decide in accordance with international law, such disputes shall apply treaties or conventions, international customs, general principles of law and lastly judicial decisions and teachings subject to Article 59 of the Statute of the International Court of Justice. These are widely recognized as the most authoritative and complete statement as to the sources of International Law ((Supra n. 2, p. 70)). Other and alternative sources has time an again been suggested by jurists and learned academics but the traditional analysis of the sources continues to dominate. This is highly questionable.

Additional Source – Equity

At the time PCIJ Statute was drafted, it was considered to complete and exhaustive. However, subsequently with time it was witnessed that there is a difficulty is considering the above-mentioned proposition, as there were additional sources, which had been discovered. Equity was one of them. Equity has been seen as a set of principles constituting the value of a system ((Supra n. 2, p. 106)). There are innumerable cases, which illustrate the role of Equity in International Law. The most famous decision was of Judge Hudson in the Diversion of Water from the Meuse case ((PCIJ, Series A/B, No. 70, p.73, 77; 8 AD, p. 444,450))in 1937 regarding a dispute between Holland and Belgium. ‘Hudson pointed out that what are regarded as a principle of equity have long been treated as a part of international law and applied by the courts ((Supra n. 2, p. 106)).’ ‘Under Article 38 of the Statute’ he declared, ‘of not independently of the article, the court has some freedom to consider principles of equity as a part of International law which it must apply’. Another case called the Rann of Kutch Arbitration between India and Pakistan ((1968, 50 ILR, p.2)), which explicitly mentioned that equity formed a part of international law and the parties, could rely on such principles in presentation of their cases ((Supra n. 9)). Therefore, it could be concluded by the above-mentioned examples that ‘Equity’ could be considered as one of the possible additional sources of International law and requires recognition.

However, in the North Sea Continental Self case ((ICJ Reports, 1969, pp. 3,53))it has been contented that Equity has been used by the courts as a way of mitigation certain inequities, not as a method of refashioning nature to the detriment of legal rules ((Supra n. 2, p. 107)). Nevertheless, the use of the principles of equity independently has also been witnessed in the subsequent years. It was particularly marked in the 1982 law of Sea convention. The use of equity was seen to be used in the grey areas between two provisions. Provision which possessed flexibility but which are uncertain. Examples of such provisions are Article 59 ((Conflict between costal and other state regarding the exclusive economic zones)), Article 74 ((Delimitation of the zones between states with opposite or adjacent coasts)), Article 83 ((Delimitation of the continental shelf))also the Convention on the law of the Non- navigational Use of International Watercourses, 1997 ((Supra n.2, p. 108)). Therefore, even if its existence as distinct source could be questioned by its inter dependent nature on existing law, yet not to provide credit to such widely used concept would be unjustified. Equity to be considered as creating legal right and obligations independent of other sources would help to uphold morality and abstain from any tragedy of the commons. In my opinion, Equity is like a shield to International Law and therefore demands recognition as a source of International Law.

Unilateral Acts

Unilateral Acts are another type of additional source, which could be considered as a source to international law. It has an ability to create obligations, which is said to be one of the characteristics of the sources. A case, which could be considered in this connection, is the case Nuclear Test case in which the court assumed that France has assumed legally binding obligation through a unilateral declaration to the world at large. It declared that it would not hold any atmospheric nuclear tests in the Pacific ((Malcom Evans (ed.), Hugh Thirlway, THE SOURCES OF INTERNATIONAL LAW, (2014), 111)). The court in this case laid down the rule in following term: ‘It is well recognized that declaration made by way of unilateral acts, concerning legal or factual situation, may have the effect of creating legal obligation… when it is the intention of the state making the declaration that it should become bound according to its terms, that intention confers on the declaration the character of a legal undertaking ((Nuclear Tests (Australia v. France) Judgment, ICJ Reports 1974, p 253, para 43)).’ Therefore, the key for unilateral acts to be considered as one of the sources would be the intention of the state to be bound by the declaration made by it is crucial and well as the element of publicity or notoriety ((Supra n. 2, p. 122)). Another type of a unilateral declaration, which could be referred to in this regard, could be the Truman Proclamations, which were made by the then U.S. President Harry Truman in 1945. These proclamations also referred as unilateral declaration formed an inspiration for claims by other states. And these formed an influential part in the preparation of the Geneva Conventions. These declarations exhibit the entire key element for a unilateral act to be considered as a source. Nevertheless, to consider it to be a distinct source of international law would be far fetched, as consent to these obligations is quintessential on part of other states. And which could only be obtained if these unilateral acts boiled down to a treaty. Nuclear test case, in my opinion could be considered an exceptional case yet not satisfying to create a new source.

Resolution of UN General Assembly

It is to be observed that, in fact the source given in Article 38(1) of ICJ is capable to perpetuate to some extend developing new laws and identifying existing laws ((Supra n. 2, p. 114)). The terms of Article 38 (1) and the disorganized state of international law is the justification for this contention. However, with the gradual de-Europeanisation of the world and the growth of the importance of the third world country the burning issues concerned in this section is the standing of the resolution and declaration of the General Assembly of the UN. Could this also be contemplated as one of the additional source of International law?

We witness in the Nicaragua case ((ICJ Reports, 1986, p. 14, 99-100))wherein it was expressed that the opinion juris requirement could be acquired from the circumstances surrounding the adoption and application of a General Assembly Resolution. It is also to be noted that the way the states vote in the General Assembly and the explanation given upon such occasion constitute evidence of state practice and state understanding of law ((Supra n. 2, p. 115)). This itself exhibits that resolutions are complete in it and would not require the support of a formal source for its standing as an independent entity. Therefore, the requirement of state practice and opinion juris for a law to fall under the Clause 2 of article 38(1) is satisfied in itself. Another example in this connection would be the 1960 Declaration on the Grating of Independence to Colonial Countries and People. It was adopted by no opposition and only nine abstentions and followed a series of resolutions in general and specific term. Consequently it culminated to a legal right and obligations, particularly taken in conjunction with the 1970 Declaration on the Principles of International Law ((Supra n. 2, p. 116)). Another Declaration such as the Legal Principles Governing Activities of States in the Exploration and use of Outer Space is an example of state practice and such resolution be the evidence of the existence of or evolution towards opino juris. However, this slows down the process of Decision making as one of the key element of customary international law require the growth of the existence of opinion juris. But, it is to be noted that when an resolution is passed it General Assembly, its passed with a majority which itself exhibits state practice. And to wait for an opinion juris to develop would be futile. Instead a strong mechanism with effective functioning can be brought into place if these resolutions have are to be considered as one of the possible sources. It would also lead to active participation of the members of the General Assemble and help in the evolution of something called the international Legislature.

It is argued that there is a danger if legal value is ascribed to everything that emanates from the Assembly. Resolutions are often the result of political compromises and arrangement and comprehended to not have binding norms ((Supra n. 2, p. 117)). But the flip side of this argument could be that every decision taken internationally by way of treaty, custom etc. or in the Domestic Legal order is a result of the interplay between politics and law. It comprises of the same elements as mentioned above, but in most cases we do witness that greatest good for greatest number is upheld. If these resolutions are given the standard as a formal source of International Law, in my opinion the rather ambiguous sphere of International Law would become more definite and the world would come more in proximity to deal with broader issue of the world at large. Therefore, Resolution of the General Assembly should be regarded as a source of international Law.


Thus, to conclude, it should be taken note that even though Article 38(1) is regarded as the enumeration of the sources of International law, the term ‘Sources’ has not been used in the Article itself. Therefore to attribute it such a tag would constrain it very nature of International law. Instead it would be feasible to regard Article 38(1) as guidelines to International law or as many learned academic suggest it to be regarded as ‘recognized manifestation of International Law ((Supra n. 1, p. 95)).’ Also, doing this would lead to the acceptances that there are additional sources apart from those mentioned. Therefore, after making the above observation, in my opinion, the sources enumerated in Article 38 (1) of PCIJ are not exhaustive.

The Legacy of International Law: Sources

Author: Pankhuri Agarwal, Research Associate

Theories as to the Origin of International Law     

Rules and norms of any legal system derive its authority from their authentic and certain sources. The source of domestic legislations can be legitimated from the mechanical system of constitution, legislature, executive and judiciary which effectuate such laws backed by sanctions. The arena becomes dwindled in the international scenario for the deficiency of specific codified text, body or institution for the purpose. Many raised their eyebrows upon its authority due to complete uncertainty about the origin of International Law. The doctrine of positivism teaches that International Law is the sum of rules by which states have consented to be bound, and that nothing can be law to which they have not consented to be bound ((Andrew Clapham, Brierly’s Law of Nations: An Introduction to the Role of International Law in International Relations, Oxford University Press, 7th ed., 2012, p. 49.)). The positivists believe that International Law can in logic be reduced to a system of rules depending for their validity only on the fact that states have consented to them ((Joseph Gabriel Starke & Ivan Anthony Shearer, International Law,  Butterworths Law, 1st ed., 1994)). Anzilloti, Triepel, and Oppenheim, the proponents of ‘consent theory’, believe that the states are bound to follow customary rules of International Law because they have given their implied consent for its acceptance ((David J. Bederman, Spirit of International Law, University of Georgia Press, 2002)). This theory is untenable for when a rule, formulated by an impressive number of acts of consent emerges as a customary rule, it becomes as such, a rule of law applicable to all, regardless of whether a state accepts or rejects it thereafter ((Bernard Kishoiyian, The Utility of Bilateral Investment Treaties in the Formulation of Customary International Law, 14(2) Northwestern Journal of International Law & Business, 1993, If consent is all that required then custom will be another name for unwritten treaties ((Ibrahim F.I. Shihata, The Treaty as a Law-Declaring and Custom Making Instrument, 22 Revue Egyptienne De Drorr International  51 (1966).)). There are rules which are applicable on states even though they had not given their consent for them. The theory breaks down in the case of a new state being admitted to the family of nations becomes bound by the body of rules in force without expressing its consent thereto except for the customary law where again all nations expect the new state to comply with the existing rules, thus leaving no choice for that new State ((S.K.Verma, An Introduction of Public International Law, PHI Learning Pvt. Ltd., 1998.)). According to Article 2(6) of the UN Charter, the Organization shall ensure that non-Members also act in accordance with its principles ((Repertoire of the practice of the Security Council, United Nations, The positivists restrict the sources of International Law only to customs and treaties. This view is unsustainable in light of the Article 38 of the Statute of the International Court of Justice.

International Court of Justice: Article 38

While the debates were on the peak, the commendable job of International Court of Justice in lieu of specifying the methodological approach to the disputed before it, Article 38 has been construed as giving the direction to the definition of sources of International Law. It identifies five sources, which can be classified under two broad categories:-

A. Formal Sources: (What is the Law?)-

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;

B. Material Sources: (Where the Law is?)-

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.

The present discussion aims to comprehend the different sources of International Law in light of their content, purpose, and validity and applicability.


The Article does not mention the term ‘treaty’ but, the same has been deduced from the term ‘conventions’. There is a rule of customary International Law of pacta sunt servanda which requires all States to honor their treaties ((Christopher Greenwood,  Sources of International Law: An Introduction, United Nations, The scholarly analysis and experiences has divided treaties into two types: a) traite lois, b) traite contracts. The former being the multi party treaty bears the law making characteristic and the later tends to bear the contractual feature as it is between relatively few parties. The ‘law making treaties’ may be of two kinds:

a) enunciating rules of universal International Law;

b) laying down general or fairly general rules ((J. G. Starke, Introduction to International Law, Butterworths Law, 10th  ed., 1989)).

The traditional perception of the treaty being only restricted to its parties, now needs to be modified with the inclusion of the modern treaties which

1) establish a special international regime or

2) establish an international organization.

A good example is the Vienna Convention on the Law of Treaties, 1969. Less than half the States in the world are parties to it but every court which has considered the matter has treated its main provisions as codifying customary law and has therefore treated them as applying to all States whether they are parties to the Convention or not. The law making treaties have the tendency to merge into the customary International Law and hence enjoys the preferential treatment over the customs.  Treaties are not intended to derogate from customary law, and a treaty which seemingly modifies or alters established custom should be construed so as to best conform to, rather than derogate from, accepted principles of International Law ((Rebecca Wallace & Olga Martin-Ortega, International Law, Sweet & Maxwell, 6th ed.)). A treaty will not however prevail over prior customary law if the latter is jus cogens ((League of nations Official Journal (1920), Sp. Supp. No. 3, p. 45)). The perfect example is the Article 53 of Vienna Convention on the Law of Treaties, 1969 ((Article 53: “A treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general International Law”)).


Custom in International Law is a practice followed by those concerned because they feel legally obliged to behave in such a way or due to a feeling that non-compliance would produce legal consequences imposed by other members of the international community ((supra at 10)). The factum of a custom can be analyzed in the light of the excerpt by ICJ in North Sea Continental Shelf Case ((I.C.J. Rep. 1969, p.3)):

“Although the passage of only a short period of time is not necessarily, or of itself, a bar to the formation of a new rule of customary International Law… an indispensable requirement would be that within the period in question, short though it might be, State practice … should have been both extensive and virtually uniform in the sense of the provision invoked; and should moreover have occurred in such a way as to show a general recognition that a rule of law or legal obligation is involved ((ibid)).”

Further, the psychological element of custom to be considered as the source of International Law can be understood in following excerpt:

“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 ((Military and Paramilitary activities in and against Nicaragua (Nicaragua v The United States) (Merits) I.C.J. Rep. 14, p. 98.)).”

The opinion juris or belief that a state activity is legally obligatory, is the factor which turns the usage into a custom and renders it part of the rules of International Law.

General Principles of Law Recognized by Civilized Nations

Mere presence of certain treaty obligations and customs creates a tricky situation for the International Courts to decide variety of issues involved in a dispute. This creates non liquet situation and thereby the gaps were resorted to be filled through referral to the general principles of law recognized by civilized nations. The general principles are those which are common to the major legal systems of the world for example, the civilian legal system, the common law system and a hybrid system ((supra at 10)). At this juncture, the intricacies involved due to overlapping of equity and general principles lead to an assumption that equity might be a source of law. But the closer analysis of the proposition unveils the fact that equity in itself cannot be a source of law for it does not contribute to substantive law, however it can, nevertheless, affect the way substantive law is administered and applied ((ibid.)).

Judicial Decisions

Judicial decisions may be applied subject to the provisions of Article 59 which mandates that the decision of the court has no binding force except between the parties and in respect of that particular case. It must be noted that though ICJ does not prescribe the compulsory rule of stare decisis, but the court in normal parlance owing to the jurisprudential concept of ‘legitimate expectation and certainty has tried to follow its past decisions to the extent possible and applicable. The non exclusion of the rulings of the national court in Article 38, national decisions can be used as a persuasion while the international judgments being delivered by ICJ. There are two ways in which the decisions of the state court may lead to the formation of rules of International Law ((supra at 9.));

a) decision may be treated as weighty precedents, or even as binding authorities

b) decision dictate the formation of custom leading directly to the growth of customary rules of International Law.

Unfortunately, the biasedness towards the powerful developed countries is being showcased for the decisions of US, UK etc are given primary importance. Writings are a subsidiary means of determining what the law is on a certain issue at a particular point in time and have a continuing role to play given the absence of stare decisis in International Law ((supra at 10.)).


The above direction as to the definition of International Law though exclusively stated in the ICJ, the experts have also included other aspects within the ambit of sources of International Law. Acts of International Organizations forms soft law for the purpose of International Law whereby the non-legally binding international instruments are collected in the written form. Some examples of it are: Universal Declaration of Human Rights, 1948, the Charter of New Paris for a New Europe, United Nations General Assembly Resolutions. Regional organizations like Council of Europe, The European Union, The Organization of American States, and The African Union represent what a particular regional grouping of States consider to be the law. The International Law Commission, a subsidiary organ of the General Assembly was established in 1946 with the task of progressive development and codification of law according to Art.13 of the UN Charter. The article 15 of Statute of the International Law Commission states that “the expression “progressive development of International Law” is used for convenience as meaning the preparation of draft conventions on subjects which have not yet been regulated by International Law or in regard to which the law has not yet been sufficiently developed in the practice of States. Similarly, the expression “codification of International Law” is used for convenience as meaning the more precise formulation and systematization of rules of International Law in fields where there already has been extensive State practice, precedent and doctrine.” Jus cogens is a body of peremptory principles or norms from which no derogation is permitted and which may therefore operate to invalidate a treaty or agreement between states to the extent of the inconsistency with any of such principles or norms ((E.Suy, The Concept of Jus Cogens in Public International Law, 1967 in, Lagonissi Conference on International Law, Papers and Proceedings, Vol. II: The Concept of Jus Cogens in International Law, (Geneva 1967).)). Article 53 of Vienna Convention on Law of the Law of Treaties is a perfect example of it. The Article 38 of ICJ in absence of any such authoritative pronouncement has assumed so much of importance that the sources are being preferred in the hierarchical form as prescribed in it, even though no such provision or clause is present to that effect. The tremendous horizontal and vertical expansion of International Law dispels the aura of doubts as to its legality and authority, serving the greater purpose behind the institution of International Law. The International Criminal law and International Humanitarian law have emerged as separate branches of International Law for the protection of the humanity. The silence as to the repeated questions of the sources of International Law will be applauded for then the larger humanitarian interests can be served better.

Judicial Decisions: What kind of Source of International Law?

Author: Evangelia Linaki, Research Associate

It seems to be a fact that there has been a great increase in the number of specialized international courts ((E.g. International Criminal Tribunal for the Former Yugoslavia, International Criminal Tribunal for Rwanda, International Criminal Court, International Tribunal for the Law of the Sea, Special Tribunal for Lebanon etc.)), raising, on the one hand, concerns as to whether such evolution will benefit the international legal order and, reinforcing, on the other,the ongoing controversy on several issues, such as the sources of International Law. It is evident, nowadays, that the core of formal sources, namely treaties, custom and general principles of law, is being highly contested by the emergence of new forms that could play the role of a formal source ((E.g. Judicial decisions and soft law instruments (United Nations General Assembly Resolutions, Declarations, Guidelines etc.).)).

Judicial decisions are one of the many elements which have long casted shadow on the monopoly of the established formal sources. Therefore, in the next few pagesa short presentation of the contradicting views on the legal status of judicial decisions, the existence and the role of judicial precedent and the contribution of international judges to the promotion of International Law will be provided. It should be noted that, since it is not possible to cover all international courts and tribunals, the International Court of Justice (ICJ) will be the point of referenceas it is regarded as the most influential forum which is likely to affect the nature and evolution of general Public International Law.

Legal status of judicial decisions and judicial lawmaking

The legal status of judicial decisions and whether international judges contribute to the making of International Law or not seem to be highly interrelated, since there is a tendency to relate the law-making potential of judges with the legal status that judicial decisions should enjoy in International Law.

It is claimed, on one hand, that judicial decisions do not constitute a primary source of International Law, like treaties, custom or general principles of law, but they serve only as subsidiary means for the determination of rules of law. Such claim is derived from Article 38(1)(d) of the ICJ Statute, which states that the Court shall apply judicial decisions as subsidiary means ((Statute of the International Court of Justice (1945) at Chapter II, Article 38(1)(d) available at (accessed 7/8/2013).)). In reinforcement of this argument, special attention must be paid to the travauxpréparatoires of the Statute of the Permanent Court of International Justice (PCIJ), which was bequeathed to ICJ itself ((Donilenko, G.M., Law-Making in the International Community, at 254 (1993).)). During the drafting of the PCIJ Statute and the determination of the Court’s mission, there was general consensus among the members of the responsible for the Court’s establishment 1920 Advisory Committee on Juriststhat a law-making task should not be appointed to the World Court with its chairman, Baron Descamps noting that “doctrine and jurisprudence no doubt do not create law, but they should serve only as an elucidation ((See id., at 254-255 andvan Hoof, G.J.H., Rethinking the Sources of International Law, at 169-170 (1983).)).”

Evidently, the drafters of the ICJ Statute did not envisage the Court to become a law-making organ but rather one that will only apply existing rules of law for the settlement of disputes ((See Donilenko, supra note 4.)). At this point, attention must be drawn upon Article 59 of the ICJ Statute, which states that a Court’s decision is binding only on the parties involved in the dispute ((See Statute of the International Court of Justice, supra note 3, at Chapter II, Article 59)). Hence, this provision does not create legal obligations for any other State and, subsequently, no precedent necessary for the enrichment of the corpus of International Law ((McWhinney,E.,The World Court and the Contemporary International Law-Making Process, at 2 (1979).)). Oppenheim’s remark that the judges’ role is of inferior importance due to a lack of lawmaking capability ((Swart, M., Judges and Lawmaking at the International  Criminal Tribunals for the forner Yugoslavia and Rwanda, at 79 (2006).))has been confirmed by the ICJ itself in the South West Africa Cases by underlining that “its duty is to apply the law as it finds it, not to make it ((South West Africa Cases (Ethiopia v. South Africa, Liberia v. South Africa), Second Phase, Judgmentof18 July 1966, 1966 ICJ Rep. 6, at 48, para.89)).”

On the other hand, there are authors who claim that judges do contribute to the development of International Law and, therefore, judicial decisions should be regarded as a source of International Law ((See Donilenko, supra note 4, at 260, Swart, M., Judicial Lawmaking at the ad hoc Tribunals: The Creative Use of the Sources of International Law and ‘Adventurous Interpretation’, 70ZaöRV, issue 3 (2010), available at (accessed 7/8/2013), Boyle, A., &Chinkin, C., The Making of International Law (2007) and Guillaume, G., Le precedent dans la justice et l’arbitrage international, 137 Journal du droit international, issue 3 (Juillet – 2010).)). Firstly, it is possible that, despite the provisions of Article 59 of the ICJ Statute, a judgment can have an effect on the interests of a Third State and, that fact is confirmed by Article 62 of the ICJ Statute, which provides a Third State with the right to intervene ((See id.,Donilenko,at 256)). Moreover, the Court’s judgments can contribute to the creation of new customary rules through the interpretation process of a treaty; the elucidation of customary rules; the reformulation and application of rules ((See id.,at 256-257 and Swart,supranote 11, at 478)); and the formulation of a new rule which will bring about the indispensable-to-the-creation-of-custom state practice ((See Boyle&Chinkin,supranote 11,at 283)). The same evolution has been observed in the field of jus cogens, since it was the judges and the arbitrators that crystallised such norms ((SeeGuillaume,supranote 11, at 702)). Lastly, judicial decisions are of paramount importance in case of lacunae in the law, such as in International Criminal Law, since judges will have to fill any gaps and respond to the vagueness or ambiguity of certain rules ((See Swart,supranote 9, at 65-66)).

Taking all of the above into account, in the author’s opinion, the subsidiary nature of judicial decisions does not pose a threat to the law-making potential of judges, rather it serves to maintain the balance between courts and States. In other words, it is the States’ sovereign right to develop law at will and it is widely accepted that they would not have accepted a World Court with law-making duties ((See Donilenko,supranote 4)). Nevertheless, the contribution of the judges to the promotion of International Law is evident, should one take into account cases, such as theCorfu Channel Case and the Armed Activities Case ((In the Corfu Channel case the ICJ ruled that every State’s obligation not to allow its territory to be used for acts which will violate the rights of the other States constitutes a well-recognised principle (Corfu Channel (United Kingdom of Great Britain and Northern Ireland v. Albania), Merits, Judgment of 9 April 1949, 1949 ICJ Rep. 4, at 22). In the Armed Activities Case the ICJ characterised Article 2(4) of the Charter of the United Nations on the prohibition of the use of force as “a cornerstone of the United Nations Charter” (Armed Activities on the Territory of the Congo (Democratic Republic of Congo v. Uganda), Judgment of 19 December 2005, 2005 ICJ Rep. 168, para. 148).)), through which customary rules and general principles of International Law have been crystallised.

One could assess the contribution of judges by comparing the impact they have when acting in their official capacity as judges rather than as international lawyers. In other words, judicial decisions have much greater influence exactly because States have recognized the official jurisdiction of the Court, whereas the judgment creates legal obligations for the parties and the “Court’s pronouncements are taken into account by governments arguing before the Court and in extra-judicial contexts ((See Donilenko,supranote 4,at 256)).” Additionally, it is of utmost importance that judges not only seek and apply law but they also exchange views, concentrate on the issues at hand and reach a decision knowing they have a collegiate responsibility ((See Boyle&Chinkin, supra note 11, at 269 and Wickremasinghe, C. (ed.), The International Lawyer as Practitioner, at 137 (2000).)). As Fitzmaurice has put it, “when an advocate before an international tribunal cites juridical opinion, he does so (…) because it contains a particularly felicitous or apposite statement of the point, and so on. When he cites an arbitral or judicial decision (…) hecites it as something which the tribunal cannot ignore, which it is bound totake into consideration and (by implication) which it ought to follow unlessthe decision can be shown to have been clearly wrong (…) ((Jennings,R.Y.,The judiciary, international and national, and the development of international law, 45 International and Comparative Law Quarterly, issue 1, at 9 (1996).)).”

Precedent in International Law?

There has been great controversy on whether a doctrine of precedent exists in International Law, having, on the one hand, those who focus on the constraints imposed to the Court by Articles 38(1)(d) and 59 of the ICJ Statute. It is claimed that since judicial decisions bind only the States involved in the dispute, no obligations are created for Third States or for previous decisions to be applied in future litigations ((See Donilenko,supranote 4, at 253)). Consequently, no doctrine of precedent exists ((See id.))and each case should be treated as special ((vonBogdandy, A. &Venzke, I. (eds.), International Judicial Lawmaking: On Public Authority and Democratic Legitimation in Global Governance, at 40 (2012).)). Moreover, it is claimed that, since judicial decisions are not formal sources of law, they do not bear any real effect on International Law ((See id., at 43)).

It is, nevertheless, believed that previous cases are more influential in reality, since invaluable legal reasoning can be found in older judgments ((See von Bogdandy&Venzke,supranote 24, at 44)), a fact which in turn may contribute to the crystallization or resolve the ambiguity of a customary rule, jus cogens or bring about the existence of an obligation ergaomnes ((See Boyle &Chinkin, supra note 11, at 295-296)).  Furthermore, by referring to previous cases, the impression that judges apply and do not create law is created ((See von Bogdandy&Venzke,supranote 24, at 45)), whereas precedent assures that all litigants are equally treated ((See Guillaume,supra note 11, at 703)). Additionally, “precedents can save time and work ((See von Bogdandy&Venzke, supra note 24)),” a fact especially important for the international courts that have to deal with a multitude of cases. Lastly, precedent can also lend a sense of predictability, security and order in a highly decentralized international community ((See Guillaume, supra note 29.)).

From the author’s point of view, notwithstanding the inexistence of a precedential doctrine, judicial decisions influence greatly the international legal order, since many a case constitute a landmark in International Law and have never ceased being cited both by the International Courts and international lawyers ((See Boyle&Chinkin, supra note 11, at 293)). As it has been mentioned, past decisions can have strong law-making potential, since they contribute to the creation of custom, jus cogens or obligations ergaomnes. It should be highlighted, nevertheless, that strong adhesion to past cases is not advised, rather they should be treated with caution so as not to preventfurther development of International Law ((See Guillaume, supra note 29))and the adaptation of law to the needs of the international community.


It has been shown that judicial decisions are confronted in two different ways: they are either considered as subsidiary means for the determination of rules of law, an argument based on the ICJ Statute itself, or as having the potential to be elevated at the sphere of formal sources. This controversy is highly interconnected with and affected by both the force of precedent and the role of international judges as law-makers. It is claimed, on the one hand, that precedent does not exist in the international legal order, since judgments are binding only upon the parties to dispute; on the other hand, practice has shown that past cases are highly cited both by the Courts themselves and the international community and they can have a multiple role to play. Consequently, it is thought, on the one hand, that judges only apply law and, on the other end of the scale, that they contribute to the promotion of law in generating or crystallizing custom,juscogensnorms and general principles. It is incontestable that International Courts have long contributed to the evolution of the international legal order and it is expected that they will continue to do so, a fact that foretells that controversy on the place judicial decisions should have is about to be continued and reinforced

An Introduction to Sources of International Law

Author: Donia Joevion Fuller, Research Associate

The clearest exposition on what one may consider as a source of law is to be found in Article 38(1) of the Statute of the International Court of Justice (ICJ), which states:

  • The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:

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.

Put succinctly, sources of law fall into four categories, international treaties, customary international law, general principles of law and judicial decisions coupled with teachings of the most highly qualified publicists. This Article aims to show the operation of each source of law and how they may of potential benefit to any international tribunal called upon to settle disputes.

International Conventions and the theory of Pacta Sunt Servanda

The Vienna Convention on the Law of Treaties, 1969 (VCLT) stands as the authoritative position on the operation of international conventions, more commonly called treaties.  The Convention defines a treaty as, “ an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation ((Article 2 (1) (a) VCLT, 1969)).” Central to the operation of treaties, and arguably in keeping with the notion of State sovereignty is that states may contract themselves to any term; consequently, a treaty may have its own mechanism for enforcement and dispute resolution. In the absence of such clear provisions, the VCLT may act as a guide on how to operate.

The issue of state sovereignty also features in the discourse of why states adhere to their treaty obligations. In this regard, the principle of pacta sunt servanda is of utmost importance. Article 26 of the VCLT stipulates that, “Every treaty in force is binding upon the parties to it and must be performed by them in good faith.” Despite the fact that there is no way to manually coerce states into performing their international obligations as against another state, one must recognize that the operation of international politics is such that economic pressure by one party brought to bear on another may be a viable mechanism to secure compliance. In addition, particularly as it relates to developing countries that rely on aid from the European Union and other international organizations, compliance with human rights treaties such as the International Covenant on Civil and Political Rights features largely in the decision whether or not grants will be meted out to various territories. In recent months, Refugees International (RI), a Washington based international advocacy group for lifesaving assistance and protection for displaced people, urged the Obama administration to withhold assistance to the government of South Sudan over alleged human rights abuses by its army (SPLA) in Jonglei state. Similarly, the European Parliament threatened to halt funds to Egypt, citing Port Said death sentences, human rights violations, and lack of political consensus in Egypt.

Customary International Law- Opinio Juris and State Practice  

By virtue of being a treaty itself and having been widely accepted by the international community as the authority on the interpretation of treaties, the principles enshrined in the document illustrate the operation of customary international law ((Frederic L. Kirgis, “Reservations to Treaties and United States Practice,” ASIL Insights (May 2003), available at Customary international law as defined by the ICJ Statute is a general practice accepted as law. The ICJ itself stated in the North Sea Continental Shelf Case: “It is of course axiomatic that the material of customary international law is to be looked for primarily in the actual practice and opinio juris of States ((ICJ, Continental Shelf case (Libyan Arab Jamahiriya v. Malta), Judgement, 3 June 1985, ICJ Reports 1985, pp. 29–30, para. 27.)).” This profound statement is taken by many scholars to mean that in order to establish that there is a principle or rule of customary international law, there are two facets that must be observed. Firstly, there must be evidence of State practice (usus) as well as  a belief that such practice is required, prohibited or allowed, depending on the nature of the rule, as a matter of law (opinio juris sive necessitatis).

Reverting to the opening statement relating to the VCLT, for a fact, less than half of the recognized States of the international community are actually parties to the treaty. Yet, the Courts have consistently considered its provisions as codifying customary law ((Anthony Aust, Modern Treaty Law and Practice (2nd edn. CUP, Cambridge 2007) 7–8 and n7))and have therefore treated them as being of general application to all states irrespective of their status in relation to the treaty. For instance, in the Kasikili/Sedudu Island Case the ICJ held that Article 31 of the VCLT relating to the interpretation of treaties reflected customary international law. Consequently, it was applicable to the case notwithstanding that neither Botswana nor Namibia was parties to the VCLT ((Case concerning Kasikili/Sedudu Island. (Botswana / Namibia). Judgment of 13 December 1999. para 18)).

For this reason, it is understandable that a fairly high threshold must be met when asserting that both elements are met and two cases from the ICJ in particular illustrates this proposition. On the hand the Case of the SS Lotus expressly showed that State practice in the absence of opinion juris will not suffice and the Advisory Opinion on Nuclear Weapons ((Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, I.C.J. Reports 1996, p. 226, International Court of Justice (ICJ), 8 July 1996, available at: [accessed 7 August 2013]))shows the converse to be true ((France. v. Turkey, 1927)). Despite the general acceptance of this definition however, it remains problematic when one considers that some international rules are permissive and reflect a belief in a right more so than an obligation. For this reason, the better view may be to consider opinion juris as an expression , assertion and acknowledgment of a legal right or obligation as opposed to a belief in one.

General Principles

It is submitted that in time, general principles of law may assume more importance than even international conventions and principles of customary law. The reason for this bold assertion is that in several areas, the law is being outstripped by technological developments. For instance, in the use of unmanned weapons or drones to combat acts of terrorism along a state’s border, the UN Charter and in particular Articles 2(4) and 51 may become problematic in their application.

On the one hand, the Charter outlaws the unlawful use of force, yet recognizes the inherent right of self-defence in respect of an armed attack. Where the latter is concerned, the there are certain procedures to be carried out before an act of self-defence is affected. The nature of unmanned weapons is such response to any such attack is immediate and would bring such a response outside the scope of the Charter. Yet, in the face of the 9/11 Terrorist Attack, is it reasonable to warrant that a State potentially compromise its security by following these procedures? Similarly, based on the principles enshrined in the Nicaragua Case it is doubtful whether the use of such technology fulfils the criteria laid out where anticipatory self defence is concerned. These questions are of course beyond the scope of this Article which merely aims to delineate the content of what are broadly considered sources of international law.  Nonetheless, to the extent that as Sir Gerald Fitzmaurice observed, a principle of law, as opposed to a rule, underlies a rule and explains the reasons for its existence. A rule answers the question ‘what’ whereas a principle answers the question ‘why ((Sir Gerald Fitzmaurice, ‘The General Principles of International Law’ (1957) 92 Collected Courses of the Hague Academy of International Law, p. 7.)), it is submitted that a principle may be more readily applied to emerging problematic areas of law, than a rule of for instance customary international law.

An apt example of the application general principles may be found in the Lena Goldfields Company Case where arbitrators recognized and indeed applied principles governing unjust enrichment as a general principle of law recognized by civilized nations ((H. C. Gutteridge, Transactions of the Grotius Society Vol. 38, Problems of Public and Private International Law, Transactions for the Year 1952 (1952), pp. 125-134- The Meaning and Scope of Article 38(1)(c) of the ICJ Statute)). In the landmark Chorzow Factory Case the Court categorically observed that, it is a principle of international law, and even a general conception of law, that any breach of an engagement involves an obligation to make reparation.  Whilst a comprehensive analysis of the precise scope and use of general principles supersedes the scope of the article, it may suffice to say that these principles essentially provide a mechanism to address international issues not already subject either to treaty provisions or to binding customary rules. Such general principles may arise both from municipal law and international law, and many may actually be described as procedural or evidential principles as well as those which affect with the machinery of the judicial process ((A; Bassiouni, M. Cherif, A Functional Approach to General Principles of  International Law,  Mich. J. Int’l L. 768 (1989-1990).)).

Judicial Decisions and Teachings of the Most Qualified Publicists

It is not surprising that the ICJ should recognize the utility of judicial decisions as a source of international law. In so far as there is no operation of binding precedent in international law, dissimilar to the operation of common law jurisdictions. Further, it is just as well that no distinction is made between judicial decisions of municipal and international courts. In relation to the latter, it is submitted that these too can be evidence of what is accepted as a general principle of law and even a customary practice.

In light of the growing problem of technology outstripping international customary principles and even broadly applicable treaties, the writings of qualified publicists are insightful on the dynamics that bring to bear on particular issues, and may also be reflective of the sentiment of that writer’s country on the issue. The benefits to an international tribunal are obvious, though such writings would never be seen as declaring the law. In view of the foregoing, an question which often emanates from these discussions is whether there is a hierarchy of sources of law.

A Hierarchy of Sources?

A simple answer to the question proposed would be in the negative. However such a sparse response would not adequately explain the matrices within which sources of law operate. To that end it is submitted that cognizance must be taken of rules of jus cogens which may be defined as customary international rules of the highest order. So much so, that Article 3 of the VCLT, 1969 explicitly states that even a treaty that seeks to enforce a practice contrary to such rules is void. Examples of such rules include the rule against torture, genocide and slavery.

However, if a rule of customary international law has not attained this status, nothing precludes States from contracting in a manner that contradicts such a customary rule. How the Court will deal with any dispute where treaty and custom conflict is another matter, but presumably the principle of pacta sunt servanda would prevail, particularly as a State may find itself bound by a customary practice that it arguably had no part in solidifying to the detriment of a treaty obligation. The latter, it is submitted is one of the ultimate expressions of State sovereignty, indeed at least theoretically, a State cannot be forced to subject itself to the terms of a treaty.  The extent to which a definitive hierarchy is even useful may be at best academic. Thus, it is respectfully submitted that for States, the best resolution in this case is not necessarily to try to find a hierarchy, but merely to attempt to discover the international rules and principles governing the legality or lack thereof of proposed state action coupled with an attempt to abide by them.