Jump to Content Jump to Main Navigation
Max Planck Encyclopedia of Public International Law [MPEPIL]

General Principles of Law

Giorgio Gaja

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2021. All Rights Reserved.date: 28 November 2021

Customary international law — State practice — Recognition and enforcement — International courts and tribunals, decisions — International courts and tribunals, procedure

Published under the auspices of the Max Planck Institute for Comparative Public Law and International Law under the direction of Professor Anne Peters (2021–) and Professor Rüdiger Wolfrum (2004–2020). 

A.  The Drafting of the Provision in the Statute of the Permanent Court of International Justice referring to General Principles of Law

References to general principles of law may be found in arbitral decisions concerning international disputes well before the adoption of the Statute of the Permanent Court of International Justice (PCIJ). For instance, in the arbitration between France and Venezuela in the Antoine Fabiani Case the arbitrator said that he would apply ‘the general principles of the law of nations on the denial of justice’ and defined those principles as ‘the rules common to most legislations or taught by doctrines’ (at 117). However, only Art. 38 (c) PCIJ Statute gave great prominence to the role that general principles of law may play in international adjudication when it stated that the PCIJ was required to apply the ‘general principles of law recognized by civilized nations’ (Civilized Nations).

This wording—which was reproduced in Art. 38 (1) (c) Statute of the International Court of Justice (ICJ)—has given rise to criticism in recent times, since it appears to be based on the dated concept that only certain nations may be rightly called civilized. This criticism, which was voiced especially in Judge Ammoun’s separate opinion in the North Sea Continental Shelf Cases ([Federal Republic of Germany/Denmark; Federal Republic of Germany/Netherlands] 132–33), led to a proposal, which was, however, not insisted upon, by Guatemala and Mexico to amend the ICJ Statute by deleting the term civilized (United Nations General Assembly ‘Review of the Role of the International Court of Justice: Report of the Secretary-General’ [15 September 1971] 23–25). More significantly, this inappropriate wording may partly explain why the ICJ has been so far reluctant to refer to specific rules of one or other municipal system, lest it imply that some other systems had to be regarded as less civilized.

A perusal of the preparatory work of the PCIJ Statute shows that the drafters had different views about what the reference to general principles of law was intended to cover (Travaux Préparatoires). Baron Descamps, the chairman of the Advisory Committee of Jurists (‘Committee’) from which the text originated, had proposed to include among the rules that the PCIJ would apply ‘the rules of international law as recognized by the legal conscience of civilised nations’ (Permanent Court of International Justice: Advisory Committee of Jurists Procès-verbaux of the Proceedings of the Committee, June 16th–July 24th 1920, with Annexes 306). As Baron Descamps later explained, he meant by this ‘the law of objective justice, at any rate in so far as it has twofold confirmation of the concurrent teachings of jurisconsults of authority and of the public conscience of civilised nations’ (ibid 324). The United States of America member, E Root, held that this reference was too wide and would have empowered the PCIJ to ‘apply principles, differently understood in different countries’ (ibid 308). In the following debate, Lord Phillimore, the United Kingdom member, maintained that ‘all the principles of common law are applicable to international affairs. They are in fact part of international law’ (ibid 316). E Root then submitted an amended proposal, which referred to ‘the general principles of law recognised by civilised nations’ (ibid 344). This text was adopted by the Committee without change (ibid 567, 584, 605, and 648). In the discussion relating to E Root’s proposal, the Brazilian member, M Fernandes, suggested that the PCIJ should apply ‘those principles of international law which, before the dispute, were not rejected by the legal traditions of one of the States concerned in the dispute’ (ibid 346). On the other hand, in an often quoted passage Lord Phillimore ‘pointed out that the general principles referred to … were these which were accepted by all nations in foro domestico, such as certain principles of procedure, the principle of good faith, and the principle of res judicata, etc.’ (ibid 335) (Good Faith [Bona fide]; Res judicata). The French member, M de Lapradelle, ‘admitted that the principles which formed the bases of national law, were also sources of international law’ (Sources of International Law); however, he ‘thought it preferable to keep to a simple phrase: such, for example, as “the general principles of law”, without indicating exactly the sources from which these principles should be derived’ (ibid 335–36). These excerpts from the summary records of the debate show that the compromise text adopted by the Committee covered a division of opinions, especially on the question whether a general principle was to be regarded as part of international law only because it was already present in municipal systems. The Committee’s report did not provide any additional explanation (ibid 729), nor was there any substantial discussion on the principles of law in the debates that led to the formal adoption of the PCIJ Statute by the League of Nations (Documents concerning the Action Taken by the Council of the League of Nations under Article 14 of the Covenant and the Adoption by the Assembly of the Statute of the Permanent Court).

B.  The Reference to General Principles of Law in the Statute of the International Court of Justice

As was noted above (para. 2), in Art. 38 (1) (c) ICJ Statute one finds the same wording as in Art. 38 (c) PCIJ Statute. No discussion took place at the San Francisco Conference about the reference in the ICJ Statute to ‘general principles of law recognized by civilized nations’.

The chapeau of Art. 38 PCIJ Statute underwent an expansion. While it originally read: ‘The Court shall apply’, it now states: ‘The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply’. This change had the purpose of stressing the Court’s function with regard to international law (see the statement of Al-Faray as Rapporteur of Committee IV/1, United Nations Information Organization [ed] Documents of the United Nations Conference on International Organization: San Francisco, 1945 [United Nations Information Organization New York 1945] vol 13 Commission IV: Judicial Organization 427). It was not intended to affect the meaning of any of the references to the various sources listed in Art. 38 ICJ Statute.

GI Tunkin argued that

the amendment invalidates the understanding of Art. 38(1)(c) that was prevailing in the Commission of Jurists in 1920. It makes impossible the interpretation of Art. 38(1)(c) according to which ‘general principles of law’ are simply principles ‘common to all civilised nations’. It clearly defines that ‘general principles of law’ are principles of international law (Tunkin 525; International Commission of Jurists [ICJ]; Interpretation in International Law).

However, even the drafters of the original text had not stated that the reference to general principles of law would entitle the ICJ to decide on a basis other than international law. They had rather viewed general principles of law as part of international law.

C.  The Application by the International Court of Justice of Principles of International Law that Find a Parallel in Municipal Laws

General principles that exist in municipal systems of law do not necessarily form part of international law (International Law and Domestic [Municipal] Law). The main reason lies in the difference in structure between international society and municipal societies. This difference may make it inappropriate to transpose to international relations a principle that is part of municipal law.

When a principle exists both in municipal laws and in international law, the origin of the principle is likely to be in municipal systems, given the greater development and wider practice relating to those systems. However, the application of the principle in international law does not necessarily depend on the fact that the principle is common to a number of municipal systems.

The case law of both the PCIJ and the ICJ provides some examples of decisions in which a principle of international law was regarded as having a parallel in municipal laws. For instance, in the Case concerning the Factory at Chorzów (Germany v Poland), the PCIJ found that

It is … a principle generally accepted in the jurisprudence of international arbitration, as well as by municipal courts, that one Party cannot avail himself of the fact that the other has not fulfilled some obligation or has not had recourse to some means of redress, if the former Party has, by some illegal act, prevented the latter from fulfilling the obligation in question, or from having recourse to the tribunal which would have been open, to him (Case concerning the Factory at Chorzów [Germany v Poland] [Claim for Indemnity] [Jurisdiction] 31; see also German Interests in Polish Upper Silesia Cases).

This passage was approvingly quoted by the ICJ in the Gabcíkovo-Nagymaros Case (Hungary/Slovakia) (at para. 110).

10  In the Corfu Channel Case the ICJ noted that

By reason of [a State’s] exclusive [territorial] control, the other State, the victim of a breach of international law, is often unable to furnish direct proof of facts giving rise to responsibility. Such a State should be allowed a more liberal recourse to inferences of fact and circumstantial evidence. This indirect evidence is admitted in all systems of law, and its use is recognized by international decisions (The Corfu Channel Case [United Kingdom of Great Britain and Northern Ireland v Albania] [Merits] [‘Corfu Channel Case’] 18).

The reference to ‘all systems of law’ has apparently the purpose of confirming what is already established under international law.

11  While references to Art. 38 (1) (c) ICJ Statute are few in the jurisprudence of the ICJ, in some decisions the ICJ appeared to endorse the view that a general principle of law applied in municipal systems is relevant as such for an international court or tribunal. In a passage of the ICJ’s advisory opinion on the Effect of Awards of Compensation Made by the United Nations Administrative Tribunal, the ICJ noted that the United Nations Administrative Tribunal was ‘an independent and truly judicial body pronouncing final judgments without appeal within the limited field of its functions’ and said: ‘According to a well-established and generally recognized principle of law, a judgment rendered by such a judicial body is res judicata and has binding force between the parties to the dispute’ (Effect of Awards of Compensation Made by the United Nations Administrative Tribunal [Advisory Opinion] 53; Administrative Boards, Commissions and Tribunals in International Organizations; Advisory Opinions). The ICJ hinted again at the existence of ‘general principles of procedural law’ in the Case concerning the Land, Island and Maritime Frontier Dispute ([El Salvador/Honduras] Application of Nicaragua for Permission to Intervene [Judgment] para. 102; Land, Island and Maritime Frontier Dispute Case [El Salvador/Honduras: Nicaragua Intervening]). A reference to the principle of res judicata as a ‘general principle of law’ was made also in later decisions of the ICJ, most recently in its judgment on the Question of the Delimitation of the Continental Shelf between Nicaragua and Colombia beyond 200 Nautical Miles from the Nicaraguan Coast (Preliminary Objections) (at para. 58).

12  The ICJ may have referred to a general principle of law existing in municipal systems also in the Temple of Preah Vihear Case when it found that

It is an established rule of law that the plea of error cannot be allowed as an element vitiating consent if the party advancing it contributed by its own conduct to the error, or could have avoided it, or if the circumstances were such as to put that party on notice of a possible error (Case concerning the Temple of Preah Vihear [Cambodia v Thailand] [Merits] 26).

13  In several decisions the ICJ concluded that there was no general principle of law that could be applied to the questions raised. Thus, for instance, in the South West Africa Cases the ICJ noted that an argument raised by the claimant State amounted to

a plea that the Court should allow the equivalent of an ‘actio popularis’, or right resident in any member of a community to take legal action in vindication of a public interest. But although a right of this kind may be known to certain municipal systems of law, it is not known to international law as it stands at present: nor is the Court able to regard it as imported by the ‘general principles of law’ referred to in Article 38, paragraph 1 (c), of its Statute (South West Africa Cases [Ethiopia v South Africa; Liberia v South Africa] [Second Phase] para. 88; South West Africa/Namibia [Advisory Opinions and Judgments]).

14  In the advisory opinion on Application for Review of Judgment No 158 of the United Nations Administrative Tribunal, the ICJ held that there was no

general principle of law which requires that in review proceedings the interested parties should necessarily have an opportunity to submit oral statements of their case to the review tribunal. General principles of law and the judicial character of the Court do require that, even in advisory proceedings, the interested parties should each have an opportunity, and on a basis of equality, to submit all the elements relevant to the questions which have been referred to the review tribunal. (Application for Review of Judgment No 158 of the United Nations Administrative Tribunal [Advisory Opinion] para. 36; United Nations Administrative Tribunal, Applications for Review [Advisory Opinions])

15  Should there be a convergence of the relevant norms of municipal laws, the principle emerging from those norms may be applied by an international court or tribunal only if it is compatible with the framework of international law. For instance, the possible convergence of municipal rules concerning intervention by a third party in judicial proceedings may not be significant for international law, under which jurisdiction is based on the consent of the parties (International Courts and Tribunals, Intervention in Proceedings). When referring to general principles, especially in the passage of the South West Africa Cases quoted above (in para. 13), the ICJ has hinted at the test of transposability, but has not elaborated it.

16  The great variety of approaches that are taken on specific legal issues by municipal laws—even when they may lead to the same practical result—often makes it difficult to ascertain whether a general principle may be drawn from this source. A doubt was even expressed by H Kelsen ‘whether such principles common to the legal order of the civilized nations exist at all’ (Kelsen 539). Often general principles that may be drawn from municipal laws are only vague and of little use. The ICJ has been understandably reluctant to apply general principles in a way that would imply a selection among municipal rules and thus the use of a large amount of discretion in finding the more appropriate rule. The ICJ would not only run into the difficulty of engaging itself in a comparative analysis. It would also have to face the risk of transgressing into the application of equity (Equity in International Law), which according to Art. 38 (2) ICJ Statute would require the specific consent of the parties to the dispute. As was observed by G Fitzmaurice,

the concept of the general principles is so fluid that a quasi-legislative element would often be introduced into the Court’s decisions by any ‘bold’ application of them, and … considerable harm might be done to the desideratum of increased resort to the Court unless a reasonable predictability as the basis of its decisions can be maintained (Fitzmaurice 325).

D.  References by the International Court of Justice to Principles that are Relevant only under International Law

17  When referring to principles of international law or to general principles the ICJ often considered principles that do not find a parallel in municipal laws. Thus, for example, in the Corfu Channel Case the ICJ found that the Albanian authorities were under the obligation to notify the existence of a minefield in their territorial waters (Territorial Sea) and to warn the approaching ships of the imminent danger. The ICJ said

Such obligations are based … on certain general and well-recognized principles, namely: elementary considerations of humanity, even more exacting in peace than in war; the principle of the freedom of maritime communication; and every State’s obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States (Corfu Channel Case 22).

In its advisory opinion on Reservations to the Convention on the Prevention and Punishment of the Crime of Genocide (Genocide Convention, Reservations [Advisory Opinion]; see also Genocide), the ICJ noted that ‘the principles underlying the Convention are principles which are recognized by civilized nations as binding on States, even without any conventional obligation’ (ibid 23). Again, in its advisory opinion on Western Sahara the ICJ stated ‘the principle of self-determination, defined as the need to pay regard to the freely expressed will of peoples’ (Western Sahara [Advisory Opinion] para. 59; Western Sahara [Advisory Opinion]; see also Self-Determination). As a further example of references to principles which do not have a parallel in municipal laws, the Chamber judgment in the Frontier Dispute Case (Burkina Faso/Republic of Mali) considered ‘the principle of uti possidetis juris’ as ‘a firmly established principle of international law where decolonization is concerned’ and as ‘a general principle, which is logically connected with the phenomenon of the obtaining of independence, wherever it occurs’ (at para. 20; Uti possidetis Doctrine).

18  The relatively frequent reference by the ICJ to principles that are not part of municipal laws is explained, at least in part, by the narrow definition of customary international law that is provided in Art. 38 (1) (b) ICJ Statute. Should custom be regarded, as stated in that provision, as ‘evidence of a general practice accepted as law’, several norms of international law which are not based on treaties would not fit in the definition of custom given the scarcity of practice. Hence the reference to principles or general principles. Only in certain cases could these principles appear as an abstraction from specific norms of customary international law. This would be, for example, the case of the principle of the freedom of maritime communication, which is referred to in the passage quoted from the Corfu Channel Case (see para. 17 above).

19  Art. 38 (1) (c) ICJ Statute requires a general principle of law to be ‘recognized by civilized nations’. When a given principle is not based on the convergence of municipal laws, recognition of that principle would need to reflect the attitude that is taken in its regard by the international community, and thus essentially by States. In other words, for a principle to exist it would be necessary that States acknowledge, albeit implicitly, that this principle applies to their international relations. Thus, for instance, in its advisory opinion on Reservations to the Convention on Genocide, the ICJ noted that the principles underlying the Genocide Convention ‘are principles which are recognized by civilized nations as binding on States, even without any conventional obligation’, and that such recognition was expressed in resolution 96 (I) of the General Assembly, which marked ‘the intention of the United Nations to condemn and punish genocide as a “crime under international law”’ (at 23). As another example, in the Frontier Dispute Case, when assessing whether the principle of uti possidetis applies in international law, the Chamber of the ICJ noted that

the numerous solemn affirmations of the intangibility of the frontiers existing at the time of the independence of African States, whether made by senior African statesmen or by organs of the Organization of African Unity itself, are evidently declaratory rather than constitutive: they recognize and confirm an existing principle, and do not seek to consecrate a new principle or the extension to Africa of a rule previously applied only in another continent (Frontier Dispute Case para. 24; see also African Union [AU]).

20  When asserting the existence of a principle that does not find a parallel in municipal systems, the ICJ has only rarely accompanied its statement with an adequate demonstration of the existence of that principle in international law. A similar remark could be made with regard to the ascertainment by the ICJ of customary principles and rules of international law.

E.  The Relations between General Principles and Customary or Treaty Rules

21  Even if general principles of law are often vague, they may complement to a certain extent other rules of international law and thus contribute to filling in gaps (General International Law [Principles, Rules and Standards]). However, principles do not necessarily have a subsidiary character. Some of the principles referred to in the preceding paragraphs clearly do not have that character. In any event, their character would not depend on whether or not they find a parallel in municipal systems.

22  One cannot assume that treaty rules always prevail over general principles of law. This would normally be the case when the treaty and the general principle cover the same ground. However, a general principle could also affect the way in which a certain treaty rule is to be applied. It could impinge on the application of the treaty rule in limited circumstances. In that case it would be more appropriate to say that the principle prevails.

23  The position of general principles of law in the list of sources of international law contained in Art. 38 (1) ICJ Statute is not indicative of their rank. As Lord Phillimore pointed out during the preparatory work of the PCIJ Statute, ‘the order mentioned simply represented the logical order in which these sources would occur to the mind of the judge’ (Permanent Court of International Justice: Advisory Committee of Jurists Procès-verbaux of the Proceedings of the Committee, June 16th–July 24th 1920, with Annexes 333).

24  A general principle of law may be embodied in a treaty provision or become part of international customary law. The origin of a treaty or customary rule in a general principle of law would not be material. The ICJ gave an example of such an embodiment in the Case of the Monetary Gold removed from Rome in 1943 when it stated that ‘[t]o adjudicate upon the international responsibility of Albania without her consent would run counter to a well-established principle of international law embodied in the Court’s Statute, namely, that the Court can only exercise jurisdiction over a State with its consent’ (Case of the Monetary Gold removed from Rome in 1943 [Italy v France, United Kingdom of Great Britain and Northern Ireland and United States of America] [Preliminary Questions] 32; Monetary Gold Arbitration and Case; see also International Courts and Tribunals, Jurisdiction and Admissibility of Inter-State Applications). Certain principles asserted by the ICJ have developed into principles pertaining to customary international law. The ICJ acknowledged this evolution with regard to the principle of self-determination. In its advisory opinion on the Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965 (Chagos [Advisory Opinion]) the ICJ set as its task to assess ‘when the right to self-determination crystallized as a customary rule binding on all States’ (at para. 148).

F.  The Application of General Principles of Law by International Tribunals

25  General principles are often applied by international tribunals irrespective of whether there is a specific reference in their constituent instrument. Certain decisions refer, like the ICJ, to principles that find a parallel in municipal systems.

26  Thus, the arbitration award in the Boundary Dispute between Argentina and Chile concerning the Frontier Line between Boundary Post 62 and Mount Fitzroy stated that

A decision with the force of res judicata is legally binding on the parties to the dispute. This is a fundamental principle of the law of nations repeatedly invoked in the legal precedents, which regard the authority of res judicata as a universal and absolute principle of international law (para. 68).

Similarly, the arbitration award in the Case concerning the Loan Agreement between Italy and Costa Rica referred to the fundamental character of the principle of good faith in international law and included it among the general principles of law recognized by civilized nations (para. 14).

27  When there are differences in the way in which municipal systems address an issue, the Appeal Chamber of the International Criminal Tribunal for the Former Yugoslavia (ICTY) noted in the Tadic Case that

national legislation and case law cannot be relied upon as a source of international principles or rules, under the doctrine of the general principles of law recognised by the nations of the world: for this reliance to be permissible, it would be necessary to show that most, if not all, countries adopt the same notion … More specifically, it would be necessary to show that, in any case, the major legal systems of the world take the same approach to this notion (Prosecutor v Tadic [Judgment] para. 225).

This cautious attitude corresponds to that of the ICJ, but is more explicitly defined.

28  Other international tribunals have had less hesitation in applying general principles of law even in the presence of discrepancies among municipal systems. For instance, in BP Exploration Company (Libya) Limited v Government of the Libyan Arab Republic, the arbitrator was required to interpret the relevant contract

in accordance with the principles of the law of Libya common to the principles of international law and in the absence of such common principles then by and in accordance with the general principles of law, including such of those principles as may have been applied by international tribunals (at 303).

The arbitrator found that the corporation was entitled to compensation but not to restitution, which would have been required under certain municipal systems, because ‘[a] rule of reason … dictates a result which conforms both to international law, as evidenced by State practice and the law of treaties, and to the governing principle of English and American contract law’ (ibid 354; State Practice; see also Corporations in International Law).

29  In the first International Centre for Settlement of Investment Disputes (ICSID) arbitration award in Amco Asia Co v Republic of Indonesia (Amco v Indonesia Case), the panel found that ‘the full compensation of prejudice, by awarding to the injured party the damnum emergens and lucrum cessans is a principle common to the main systems of municipal law, and therefore, a general principle of law which may be considered as a source of international law’ (Amco Asia Co v Republic of Indonesia [Award of 20 November 1984] para. 267).

30  The selection of what is considered the better law under the guise of the application of principles of law is frequent in commercial arbitration, where the reference to general principles provides an apparently objective criterion (see also Commercial Arbitration, International). A similar approach is taken by the European Court of Justice, which only rarely refers to the pertinent rules of municipal laws and attempts to find a genuinely common denominator (European Union, Court of Justice and General Court).

G.  Assessment

31  When determining the applicable law, references to general principles of law undoubtedly provide international courts and tribunals with discretion. Only rarely could one say that a certain principle may be inferred from more specific rules of international law. While the distinction between principles and rules has not been elaborated in judicial or arbitral decisions, the use of the term principles denotes the general nature of the norm in question.

32  Principles drawn from municipal laws have been applied only with caution by the ICJ. On the contrary, some arbitration tribunals have shown less hesitation in referring to municipal systems even when they arguably offer a variety of solutions and the adoption of one or the other solution necessarily implies a considerable discretion.

33  The ICJ often asserted the existence of principles in international law irrespective of their correspondence to principles pertaining to municipal laws. The ICJ thus included in general international law norms that could not be defined as part of customary law. This aspect of the ICJ’s jurisprudence is to some extent controversial, as shown by the discussions prompted by the study of general principles of law initiated in 2019 by the International Law Commission (ILC) (UN Doc A/74/10).

Select Bibliography

Select Documents