1 Introduction
One of the leading interwar advocates of the development of international judiciary and a judge of the Permanent Court of International Justice (hereafter: pcij, or Court) in the last period of its activity – Manley Hudson, claimed that ‘the process of finding the applicable international law […] is not a discretionary process. At every step it calls for the exercise of a judgment disciplined by learning and experience’.1 This opinion supports the idea that international judges operate within a limited range of discretion. In particular, international courts and their judges should not make laws, but should only find the law as it stands and apply it. Today the International Court of Justice (icj) as the successor of the pcij evidently underlines that ‘it is clear that the Court cannot legislate […]. It states the existing law and does not legislate’.2 In this sense the International Court recognizes it as misleading to speak of its decisions as ‘law-making’ in the true sense of the term, because it is the law that constrains the judges, and not vice versa. After the Wimbledon decision the pcij declared itself to be a body responsible for the knowledge of international law. In the Brazilian Federal Loans case it stated ‘[T]he Court, which is a tribunal of international law, […] in this capacity, is deemed to know what this law is […]’.3 The position of the Court may be understood both as a statement of fact, i.e. the Court’s knowledge of law with reference to the specific cases it tried, and as
The current chapter is organized into five parts, including this introduction and the conclusions. Part ii addresses the relationship between treaties and custom in the Court’s reasoning. In this part the author seeks to indicate the sources of general international law, in particular, to answer the question as to whether law-making provisions of treaties may be seen as its formal source. In the Wimbledon case the Court argued they should, in fact, be seen as such. Part iii deals with various ways in which the Court interpreted the texts of the treaties when it handed down its final judgement. The aims, methods, and means of treaty interpretation adopted by the Court had a clear impact on the understanding of rights and duties of the parties to the proceedings as well as on third states. Therefore, they are relevant to the Court’s doctrine of sources. Part iv discusses the problem of ‘relative normativity’ under the judgment. The Permanent Court deciding the Wimbledon dispute had to address the problem of normative hierarchy, i.e. a situation when priority had to be given to a specific rule among several that might have been applicable to a legal matter or dispute. The Court’s pronouncement regarding the provisions of Article 380 of the Treaty of Versailles as a regulation of a ‘general and peremptory character’4 undoubtedly prompts consideration of this problem. The problem is intrinsic to the sources of international law. Discussing this problem, the author seeks to substantiate the proposition that, first, for the sources of international law ‘custom is more than treaty, more even than a generally accepted treaty’, as James Crawford put it,5 and, secondly, ‘relative normativity’ is intrinsic to the practice of international law-making and to the development of international law.
2
2.1 Has the Contribution of the Wimbledon Decision to the Debate on Sources Been Less than Expected, and if So, Why?
The idea of formal sources has been intensely and widely discussed, as well as criticized, by international lawyers. The ‘formal sources’ approach is championed in international law scholarship for its virtues of distinguishing law from non-law, and consequently as necessary to the ascertainment of international legal norms.6 That is why the problem of sources of law has traditionally been seen as one of the most important issues for jurists, especially from the perspective of legal certainty. The important function of the formal sources approach is to guarantee the objectivity of law. There is a close link between this approach and the ascertainment of law, since the formal sources show where the law may be found, which makes it possible to know what law is being applied.7 In every legal order, and perhaps especially in international law which lacks a legislature and a judicial system with compulsory jurisdiction, striving for a precise definition of the formal source of law seems to be a problem of great practical importance, since it makes it possible to identify the formal factors that distinguish binding legal rules from both de lege ferenda rules and such rules as may be present in social reality, but are not formally grounded in identifiable legislation. The idea of formal sources matters because its precise understanding makes it possible to determine whether or not certain rules have acquired legal validity in the process leading to their creation. This process gives the rules legal attachment, i.e., it identifies them with the legal order. It is a ‘step from the pre-legal into the legal world’, as Herbert Hart put it when he spoke of the secondary rules.8 Insofar as the formal sources of international law are concerned, both the processes and forms by which principles and rules
The contribution of the Court’s case law to the development of substantive international law was perhaps less than might have been expected. This was because most of the cases brought concerned alleged violations of specific treaty provisions, rather than of general principles of law.12
2.2 Has the Wimbledon Decision Contributed to the Theory of General International Law, or Are Treaties the Formal Source of General International Law?
the conception of the State as an international law subject was no longer the main plank of the reasoning. […] And, since the Permanent Court had departed from the conception of the State as an international law subject, its counter argument was grounded on the conception of the State as an international sovereign. Thus, in what may be termed “the Wimbledon statement”, the Permanent Court held that “the right of entering into international engagements is an attribute of State sovereignty”.15
The sovereignty issue is not addressed in this chapter.16 I mention it, however, since the Court’s concept of the state clearly influenced the justification of states’ compliance with their obligations. It is nolens volens linked to the formal sources, the relationships between them, and possible erga omnes effects of norms following from them. Thus, the concept of the state had an impact on the Court’s doctrine of sources as well as the means of interpreting them. It also affected the Court’s understanding of international law as a whole. Indeed, it is a concept of law adopted, although not always clearly articulated, that determines the perception of the structural features of legal order, including the issues of personality, law-making processes, and sources. This is, as it seems, evidenced by the discussed judgment.
It is a truism to recognize that state consent is a crucial matter for the normative validity and legitimacy of international law, and for its formal sources. Consent to be bound by treaties goes without saying. Those, however, who see the rules and principles of international law within the Lotus perspective,17 that is, as ‘emanating from the free will’ of states, seek to explain the binding force of other sources – custom and general principles of law – in the terms ‘tacit agreement’ or ‘contractual scheme’. Did the Court base its reasoning on this scheme in the Wimbledon case, and was the judgment the first step on the way to the ‘Lotus statement’? One of the commentators on the pcij’s contribution to the doctrine of sources argues that generally ‘the Court had, in fact, tried to do everything in its power to prevent the incorporation of the contractualist metaphor into the contemporary doctrine of sources debate’.18 But at the same time, this author poses a question: if this is true, why did the Court enthusiastically endorse the contractualist model in the famous dictum
the Canal has ceased to be an internal and national navigable waterway […] and it has become an international waterway intended to provide under treaty guarantee easier access to the Baltic for the benefit of all nations of the world. Under this new régime, the Kiel Canal must be open, on a footing of equality, to all vessels […], but on one express condition, namely, that these vessels must belong to nations at peace with Germany.27
Moreover, the Court recognized that those provisions relating to the Kiel Canal in the Versailles Treaty were ‘self-contained’, since ‘the Kiel Canal is open to the
The Court’s judgement that the provisions of Article 380 of the Treaty of Versailles constituted a regulation of a ‘general and peremptory character’ prompts a discussion as to whether treaty provisions can result in rights and obligations not only erga omnes partes, but also those that are applicable to all states, including non-parties to treaties, and their relationship to general international law and its sources. In its report on the fragmentation of international law, the Study Group of the International Law Commission admitted that the very term ‘general international law’ still has no generally accepted definition.31 The Study Group has defined what is general by reference to its logical counterpart, namely, what is special, and has underlined the contextual meaning of this distinction. The Court did not use the term ‘general international law’ in the judgment. But while defining the provisions of Article 380 as constituting a regulation of a ‘general and peremptory character’, the Court seemed to support a position that law-making treaties constitute formal sources of general international law, which inclines to address this proposition.
In contemporary studies on the sources of international law, this judgment serves as an example of the explaining and grounding of institutional unilateralism in the decentralized international legal order in willful submission, that is, in the act of a state’s granting of its consent, and adhering to pacta sunt servanda.32 After all, the validity of the provisions of the Treaty of Versailles proclaimed by the Court as being ‘general and peremptory’ is derived from
My contention is that such an approach did not help the Court to comprehensively determinate and convincingly substantiate the legal basis for relations between those states that were parties to the Versailles Treaty and third states that may not have been parties, i.e., the legal relations beyond the treaty regime itself. When the Court focused on the Respondent’s international legal status, it derived it primarily from its treaty rights and duties related to the Kiel Canal. The main consequence of this was to marginalize a broader legal perspective, i.e., the perspective of general international law. In particular, the Court gave a very cursory analysis of customary law regarding the duties of the Respondent as a riparian state resulting from its neutrality towards the parties to the international armed conflict, i.e., towards the Soviet Russia and Poland. The Court, on the one hand, in its adjudication of these duties in fact, discredited the significance of general international law arising from custom. On the other hand, the Court’s attribution of the ‘general and peremptory character’ standard to the treaty regulation was made, as it seems, rather exaggeratedly. At that time, speaking of such regulation was undoubtedly a normative novelty and perhaps the beginning of the ‘relative normativity’ that will be discussed in part iv of this Chapter. But, then as now, it has been doubtful whether law-making provisions of treaties could be the formal source of a regulation of a ‘general and peremptory character’. Then and now, treaties have been
2.3 The Relationship between Treaties and Custom; or Why General International Law Matters
It is a truism that the relationship between treaties and custom is a complex issue that requires careful consideration to be clarified. It has even been called a ‘paradox’ in the Wimbledon case.35 Sheila Weinberger argued that in this case the customary law of neutrality in 1921 allowed Germany to do that which the Versailles Treaty prohibited, and the ‘paradox’ existed because of coequality that treaties and custom share as sources of international law.36 According to Weinberger, the Permanent Court failed to confront this paradox because it did not treat custom and treaties as coequal sources of law and, instead, it used judicial rhetoric to avoid addressing the issue.37 In consequence, ‘the Court left States in a position of uncertainty’, as Weinberger put it.38 She also accuses the Permanent Court of an ‘intellectual dishonesty’, claiming that ‘rather than acknowledging the conflict which existed in this case, the Court used treaty interpretation and judicial rhetoric to avoid the most important issue. In the process, the Court affected the rights of a third party not before it, Russia’.39
There are, however, insufficient reasons to fully share these critical comments. First, it does not seem desirable to evaluate courts’ reasoning from
The method that the pcij used in the Wimbledon case to determine the applicable customary law has often been the topic of critical commentary. The majority of the bench in the judgment, as in the later Lotus judgment, applied an inductive approach to custom, that is, it derived a general rule from few and particular instances. Moreover, it did not actually refer to an opinio juris of states.41 In consequence, the Court found that the general practice of a custom concerning neutrality could be determined from the provisions of no more than two treaties, those being the treaties that governed the Suez and Panama Canals, wherein the number of parties was at best rather limited. The awkward result was that the Court established a customary rule binding upon Germany relying upon treaties that did not involve Germany as a party.42 Moreover, the
Spiermann, addressing the origin of the Court’s Statute, claims that the discussion in the League of Nations’ Advisory Committee of Jurists (acj) revealed a need for international law that went beyond positive rules identified with treaty and custom, and an expectation for the Court to fill the scope of general international law.44 If that was indeed the case, the Permanent Court did not live up to the expectation of most of the acj’s members. There was another need related to a new international judicial body of general jurisdiction, namely, establishing a broader framework of systemic, coherent and constitutional underpinnings for international law. There were great expectations in this regard after World War i.45 Andreas Paulus claims from the contemporary perspective that the ‘unity of the international legal system was never as great as in the interwar years, when the pcij provided some systemic coherence’.46 Indeed, in the Wimbledon judgment the Court did not find a normative incoherence between treaties and custom, and thus it seemed to opt for the substantive unity of international law. However, the fragility of its arguments on application erga omnes of the treaty rules of an alleged peremptory character hardly permits one to include this decision in the legacy of the Permanent Court’s support for a coherent framing of general international law.
The judgment in the Wimbledon case, while answering the specific question as to the meaning of Article 380 of the Treaty of Versailles, is now an authority on the status of artificial waterways of an international character, on some aspects of neutrality, on restrictive interpretation of treaties – not to mention such matters as the measure of damages and award of interest.52
However, with the exception of the last of the topics mentioned by Lauterpacht, they are all controversial to a greater or lesser extent. Led by the status of neutrality, all have been burdened with some measure of doubt.
are merely illustrations of the general opinion according to which when an artificial waterway connecting two open seas has been permanently dedicated to the use of the whole world, such waterway is assimilated to natural straits in the sense that even the passage of a belligerent man-of-war does not compromise the neutrality of the sovereign State under whose jurisdiction the waters in question lie.55
It means that this provision of the Treaty of Versailles was, in the thinking of the Court, of declaratory, and not law-making, character. Thus, it is custom, not the treaty, that was the source of this rule. The mentioned treaties on the international canals were just their supporting justification. This leads to the following conclusion regarding the contribution of the Wimbledon reasoning to the doctrine of sources: the difficulties in the Court’s identification of customary rules were responsible for an unclear concept of general international law under the judgment.
[N]eutral duties must take precedence over any contractual obligations. The violation of the duties of a neutral no doubt constitutes an offence under international law even when treaty obligations assumed towards third States can be put forward in support of such an act. It cannot have been the intention of the victorious States to bind the Reich by means of the Versailles Treaty, to commit such offences as against third States. It would, moreover, have been impossible to give effect to such an intention, because a legally binding contractual obligation cannot be undertaken to perform acts which would violate the rights of third parties.60
Indeed, state neutrality, and its legal status and normative significance is perhaps a crucially substantive topic in the case.61 That notwithstanding, the issues identified by the German judge ad hoc, in particular the intention of the parties to the Versailles Treaty, prompt consideration of the interpretation of treaties in the case.
3 Treaties and Their Interpretation under the Judgment or Does Interpretation Make International Law?
3.1 Was the Principle of ‘Systemic Integration’ Relevant to the Wimbledon Dispute?
Hersch Lauterpacht assessed that the majority of the cases, including the Wimbledon one, which came before the Permanent Court arose out of a disputed interpretation of a treaty.62 This view simply declares the inherent interdependence of application and interpretation of legal rules and principles, which leads to a question whether and how interpretation shapes international law.63 The World Court as a court of general jurisdiction was to ‘decide
The right of a State to adopt the course which it considers best suited to the exigencies of its security and to the maintenance of its integrity, is so essential a right that, in case of doubt, treaty stipulations cannot be interpreted as limiting it, even though these stipulations do not conflict with such an interpretation.72
Judge ad hoc Schücking also based his reasoning on the systemic interpretation of Article 380. He argued that the violation of the duties of a neutral no doubt constituted an offence under international law even when treaty obligations assumed towards third States could be put forward in support of such an act. According to him, however, it could not have been the intention of the parties to bind the Respondent, by means of the Versailles Treaty, to commit such offences as against third States. He finished his dissent as follow: ‘[A] legally binding contractual obligation cannot be undertaken to perform acts which would violate the rights of third parties’.74 Meanwhile, the majority of the bench seemed to reject this systemic approach. They primarily believed in the treaties as a main formal source of international law and attributed to Article 380 such a high intrinsic normative significance that they saw no need to interpret it not only against the background of international law as a whole but also in the context of Part xii of the Versailles Treaty. The judgment recognized the regulation of Article 380 as of ‘general and peremptory character’ and its terms as ‘categorical and give rise to no doubt’.75 The Court agreed that the provisions relating to the Kiel Canal were ‘self-contained’ and they would lose their raison d’être if they had to be supplemented and interpreted by the provisions in the previous Sections of Part xii. Moreover, the Court emphasized that the idea of Article 380 and the following provisions was not to ‘be sought by drawing an analogy from these provisions but rather by arguing a contrario, a method of argument which excludes them’.76
3.2 The ‘Plain Terms’, the Intention of the Parties to the Versailles Treaty, and the Interpretation of the Treaty Provisions on the Kiel Canal or Does the Restrictive Interpretation Matter?
[I]t is submitted that while a term may be ‘plain’ absolutely, what a Court adjudicating upon the meaning of a treaty wants to ascertain is the meaning of the term relatively, that is, in relation to the circumstances in which the treaty was made. If that is what is meant by the doctrine of “plain terms”, no objection is raised to it. But if it means that the Court must stop short at applying the term in its primary and literal sense and permit no inquiry as to anything further, it is submitted that the doctrine is wrong. The doctrine embodies a presumption but not an irrebuttable one, and it is reasonable to suppose that the Court will lay the burden of proof upon the party seeking to rebut the presumption.77
The Permanent Court, when speaking of the terms of Article 380 as ‘categorical and give rise no doubt’, supported the doctrine of ‘plain terms’ and gave the grammatical interpretation a crucial role.78 Besides, the Court’s recognition of the provisions relating to the Kiel Canal as ‘self-contained’ suggests that the Court saw the regime of the Kiel Canal as a strong form of lex specialis. It inclines to address the relationship between general international law and self-contained regimes, which was rather failed by the Court and what be discussed in the next part of the Chapter. It is the overall interpretative approach of the Court that needs to be addressed in this place. As said, the Court primarily relied on the grammatical interpretation to determine the rights and duties of the Respondent. Thus, it preferred the objective interpretation to the subjective or intentional one. The latter emphasizes the intention and will of the parties. The Court claimed that the terms of Article 380 ‘give rise no doubt’ and the restrictive interpretation of the limitations of sovereign rights of Germany to the Kiel Canal has to ‘stop at the point where the so-called restrictive interpretation would be contrary to the plain terms of the article and would destroy what has been clearly granted’.79 Nowadays, the ‘objective approach’
The Court’s approach to the restrictive interpretation of rights and duties of the Respondent against the background of the territorial regime of the Kiel Canal can be useful for addressing an issue of whether and how its interpretative practice shaped substantive law in the case. Essentially, the Court opted for the restrictive interpretation. It argued that the sovereign rights of the Respondent over the Kiel Canal constituted a ‘sufficient reason for the restrictive interpretation, in case of doubt, of the clause which produces’ their important limitation.83 However, as already mentioned, the Court decided it was obliged to ‘stop at the point where the so-called restrictive interpretation would be contrary to the plain terms of the article and would destroy what has been clearly granted’.84
The analysis of the Court’s interpretative practice in its first judgment leads to the conclusion that the Court noticed a new normative quality for the international law-making in treaties. It can be said that the order of enumeration of the grounds for decisions in Article 38 of the Statute was seen by the Court as a hierarchy of the normative validity of the sources. It is in the treaties, as the Court seemed to say, that the cure for the shortcomings of international law should be sought. The entry into force of a multilateral treaty of law-making character (traite-loi) was for the Court a clear evidence of the consent of its parties and their common will to ensure the effectiveness of treaty obligations, especially those of ‘peremptory and categorical character’. Whether such a position of the treaties in the international normative hierarchy is justified enough to be the source of general international law is discussed in the next part on the ‘relative normativity’.
4
4.1 Is the Normative Hierarchy Something Inherent to International Law?
In the judgment the Court stated that the provisions of Article 380 of the Versailles Treaty could not be modified or affected by the rights and duties of states following from other sources of international legal obligations. However, it did not extensively address, first, whether a treaty itself is effective enough to establish a legal regime that would be applicable erga omnes, that is, a regime that would be, in fact, effective beyond the treaty regime itself; and, second, the relationship between treaties and customary rules that were recognized as being effective erga omnes. Consequently, the judgment is said to have given a poor answer to the question as to whether and why the treaty provisions could affect the rights of third states. Nonetheless, the Court drew its attention to the normative hierarchy, that is, a situation when priority has to be given to a specific rule among several that might have been applicable to a legal dispute or matter. The normative hierarchy or ‘relative normativity’, as Prosper Weil famously labeled it,93 is relevant to the topic of sources of international law as norms in conflicts must come from somewhere, which means they are rooted in the sources understood as ‘containers’ of valid legal principles and rules.94
The Court seemed to perceive the normative differentiation among norms of international law in the case. At the same time, however, it tried to avoid deciding the normative conflict in the submitted dispute. The Court intended to support a ‘harmonization attitude’ based on a principle that when several norms bear on a single issue they should, to the extent possible, be interpreted so as to give rise to a single set of a compatible
These issues are crucial not only to the theory of international law sources, but also to the general theory of international law. Some of Weil’s critics argue that what he described as ‘relative normativity’, that is, a hierarchy of norms, is not an expression of “pathological” development of international law, but a statement of fact inherent in the nature and structure of this law.97 As Ulrich Fastenrath argues, the gradation of normativity of legal principles and rules is inevitable, which seems to be confirmed in all theories of law, including legal positivism on which Weil based his arguments.98 Law, as well as other normative orders, always operates in a social context. Therefore, Dinah Shelton claims, the substantive or material criteria of the normative validity of its rules and principles are nolens volens elements of secondary rules.99 It is a foundation of international law that the states subject to that law have agreed on the formal sources to identify binding legal obligations for the purpose of resolving their disputes, but, at the same time, they have not clearly determined a
In practice, conflicts among norms and their interpretation are probably inevitable in the present, largely decentralized international legal system where each State is entitled initially and equally to interpret for itself the scope of its obligations and the means of implementation such obligations require. The interpretations and determinations of applicable rules may vary considerable, making all international law somewhat relative, in the absence of institutions competent to render authoritative interpretations binding on all States.101
It is the absence of hierarchy among the formal sources of international law that is responsible for unclear rules governing normative conflicts between international legal regimes. Thus, it is not always unambiguous which conflicting norms prevail and what rules govern the resolution of normative conflicts. In particular, it is relevant when norms of general international law conflict with norms from a special regime. There are, however, a few possibilities to resolve such conflicts, including preventing and solving conflicts of international norms without prioritizing one over the other based on the principle of compliant interpretation or coherence also known as the principle of systemic integration.102
4.2
In the Wimbledon case, there was a conflict between the regimes on international waterways on the one hand, and those on neutrality on the other. Judging from the terms of the Wimbledon decision, the regulation of Article 380 of the Versailles Treaty defined therein as ‘peremptory’ might have been seen as a specific special regime going beyond the treaty regime.103 However, this does not go without saying, because the Court’s definition of this regulation as ‘peremptory’ did not in itself confer a peremptory nature onto the regulation. Nor did it necessarily prove that it was jus cogens, even to the Court itself.104 The majority of the bench failed, first, to decide whether the regulation of Article 380 had a law-making character, or declaratory one and, second, to compare customary international law on rights and duties of riparian states in connection with navigation through sea canals, with the treaty regulation on the Kiel Canal. Consequently, the Court did not actually find a normative conflict between the norms of general or customary law and the treaty regime of the Kiel Canal. This interpretation of the relevant law was challenged in the dissenting opinions. At any rate, the Court recognized that the Versailles regulation was a specific and special regime that might modify or qualify rights and duties of states under general international law.105 However, a crucial issue is whether a treaty regime as a lex specialis prevails over norms of general international law that are recognized as being effective and applicable erga omnes. This is what the primary problem of the Wimbledon case boils down to. It, thus, seems necessary to discuss whether and what rules of general international law should have been applied to the dispute, and whether the Court correctly shaped their relation to Article 380 of the Versailles Treaty.
As mentioned above, the Permanent Court failed to meet the expectations of most members of the Advisory Committee of Jurists, especially Edouard
The Court’s difficulties in identifying customary rules was not the only reason for its non-enthusiastic, so to say, approach to the unwritten sources of general international law. The Court also failed to use the normative potential of general principles of law in the judgment as it has recently been assessed.108 Instead, the Court based its arguments on the Versailles Treaty, but did not justify the applicability of its rules regarding the Kiel Canal towards third states, including Germany’s duties as a neutral state. The problem in the Wimbledon case in this context was whether Russia could have legitimate expectations towards Germany as a neutral state under general international law. The Court, in fact, gave a negative answer, since it adopted that free passage through the Kiel Canal was based on only one condition, namely, the belonging of vessels to states that were at peace with Germany.109 Great Britain and France were at peace with Germany when the “Wimbledon” incident occurred, and the Court argued that Germany was free to declare and regulate her neutrality in the Polish–Russian war. But neither Russia nor Poland was at war with Germany at that time either. That is why, the Court claimed, Germany was not only entitled to permit the passage of the “Wimbledon”, but that it was her ‘definite duty’ to allow it.110 The Court, in fact, assumed that the Versailles Treaty regime on the
The crucial problem for the ‘relative normativity’ issue is whether a special treaty regime, such as the Versailles regime on the Kiel Canal, can legitimately derogate rules of general international law. It seems that while special treaty regimes may make rights effective erga omnes, the exercise of these rights when third states are affected is legitimized only if it does not lead to the violation of obligations erga omnes under general international law. Therefore, a generally accepted means of interpretation and normative conflict resolution, the maxim lex specialis derogate legi generali, is not relevant in every situation concerning normative conflicts. There are certain kinds of general international law from which special treaty regimes simply may not derogate.111 In the Wimbledon case it concerned the duties of the Respondent as a neutral state vis-à-vis the Soviet Russia which might have been affected by the treaty regime on the Kiel Canal. There has been no accepted definition of general international law. The Permanent Court, however, tried to derive general law from the Versailles treaty, since it saw treaties as a remedy for the shortcomings of the international law-making process. This can explain the failings in its arguments regarding custom and the complete marginalization of general principles of law. True, the judges deciding the Wimbledon case were, as mentioned, aware of normative conflicts. But the majority of the bench, due to these failings and the adopted interpretation of the rights and duties of the Respondent as the neutral and riparian state, decided that, in fact, there was no normative conflict in the case.
Judge ad hoc Schücking in his dissenting opinion offered two important propositions for the ‘relative normativity’ problem. First, he argued that a treaty regime as a lex specialis could not derogate from generally accepted custom, which was also stressed by Anzilotti and Huber. And second, he questioned
The majority of the bench in the Wimbledon decision and the dissenting judges disagreed on the normative importance of customary law, the ways of identifying its rules, and their interpretation. These issues, as known, caused considerable problems then as they do now. The majority of the bench argued that
the precedents […] afforded by the Suez and Panama Canals […] are merely illustrations of the general opinion […] that even the passage of a belligerent man-of-war does not compromise the neutrality of the sovereign State under whose jurisdiction the waters in question lie.113
Whose ‘general opinion’ did the majority of the bench have in mind? Rather not states’ but scholars’ as most commentators argued.114 This opinion was therefore not an opinio juris of the primary members of the international community, but, ‘the teachings of the most highly qualified publicists’, that is, ‘subsidiary means for the determination of rules of law’ as defined in Article 38(1)(d) of the Statute of the World Court. Moreover, the generality of this opinion was not evidenced in the judgment. Therefore, this opinion cannot be considered as a decisive means for the determination of a customary rule that ‘passage of a belligerent man-of-war does not compromise the neutrality of the sovereign State under whose jurisdiction the waters in question lie’, as the Court claimed. The bench, in its attempt to demonstrate the normative validity of this customary rule, failed to properly identify the relevant state practice. It referred only to the treaties on the Suez and Panama Canals and the mentioned subsidiary means. That is why the Court’s position on customary law can hardly be approved.
Germany’s refusal to allow the steamship “Wimbledon” to pass through the Kiel Canal could qualify in terms of the following possibilities: there was a ‘definite duty’, as the Court claimed, to allow passage through the Canal, and therefore this refusal violated international law or, alternatively, the Respondent
4.3 Why General International Law Matters
Manley Hudson argued that if a problem ‘cannot be disposed of by the application of a provision in an agreement in force between the parties, a tribunal must take a wider search, for which numerous guides are available’.115 This view needs a short comment: even if an international court has jurisdiction to settle a dispute on the basis of a clear treaty regulation, its decision should also be grounded in general international law, since no treaty regulation exists in a legal vacuum. As a consequence, it is necessary to discuss the relationship between lex specialis and lex generalis. In this context, it is worth remembering icj Justice and former President Rosalyn Higgins’s dissent in the Nuclear Weapon case. She argued: ‘It is an essential requirement of the judicial process that a court should show the steps by which it reaches its conclusions’.116 Did the Permanent Court exercise due diligence in the Wimbledon reasoning in this respect? Rather not, since it did not address comprehensively the mutual relationships between treaty obligations on the one hand, and customary sources of rights and obligations of the parties on the other. This problem was referred to much more clearly in the dissents.
The Court in its first judgment took into account, as mentioned, the normative conflict in the submitted dispute. After all, it recognized the Respondent’s contention that was submitted in the proceedings as being ‘conflicts with general considerations of the highest order’, ‘gainsaid by consistent international practice’, and ‘contrary to the wording of Article 380’.117 This means that the legal obligations of the parties to the proceedings might arise from various sources. But to the Court, among different rules applicable to the parties, those
The Court seemed to place too much faith in the normative power of treaties. This, however, can lead to a paradox, characterized by Roger Baxter as ‘the more agreement, the less law’.120 As the Baxter paradox shows, the practice of
International law is a legal system. Its rules and principles (i.e. its norms) act in relation to and should be interpreted against the background of other rules and principles. As a legal system, international law is not a random collection of such norms. There are meaningful relationships between them.124
Indeed, the interpretative approach matters. But in the Wimbledon judgment the Court did not address these ‘meaningful relationships’ in sufficient depth, and, as a result, general international law receded into the background. In consequence, the Court was unable to clearly identify the relationship between the divergent formal sources of international law in the case.
5 Conclusion
In this chapter, the author generally sought to answer the question as to whether, under the Wimbledon judgment, treaties can be seen as a real formal source of general international law, or merely a source of legal obligations to their parties. The problem concerns the relationship of treaty obligations to unwritten sources of international law, that is, custom and general principles of law. The judgment is vulnerable to criticism for the absence of a convincing treatment of this issue. In particular, for its failure to satisfactorily identify any applicable customary rules of international law, their effects, or any relation to treaty obligations. Consequently, the Permanent Court gave a rather modest answer to the question as to whether and why the treaty provisions could affect the interests of non-party states.
Nonetheless, the Wimbledon judgment draws attention to crucial issues in the debate on the sources of international law. Firstly, it indicates that normative conflicts are something not only intrinsic to, but also useful for, the development of international law. Addressing these conflicts may contribute to the clarification of international legal norms, and the examination of what is crucial for the normative validity of general international law, that is, the universal opinio juris of states. Secondly, contrary to the Court’s reasoning, the
Hudson M.O., International Tribunals: Past and Future (Washington D.C.: 1944) 107–108.
Threat or Use of Nuclear Weapons, Advisory Opinion, icj Reports 1996, par. 18.
Case Concerning the Payment in Gold of Brazilian Federal Loans Contracted in France [1929] pcij Ser A No 21, at 124.
Case of the s.s. “Wimbledon” [1923] pcij Ser A No 1, at 21 (hereafter: Wimbledon).
Crawford J., Chance, Order, Change: The Course of International Law (The Hague: 2014) 139.
See generally d’Aspremont J., Formalism and the Sources of International Law. A Theory of the Ascertainment of Legal Rules (Oxford: 2011). See also d’Argent P., “Sources and the Legality and Validity of International Law: What Makes Law ‘International’”, in Besson S. – d’Aspremont J. (eds.), The Oxford Handbook of the Sources of International Law (Oxford: 2017) 541, 543–546; Schachter O., “International Law in Theory and Practice. General Course in Public International Law”, Recueil des Cours 178 (1982) 9, 60; Thirlway H., “The Sources of International Law”, in Evans M.D. (ed.), International Law (3 ed., Oxford 2010) 97–98. The icj’s position should also be taken into account. The icj emphasized in the South West Africa case that legal rights and obligations must have a ‘sufficient expression in legal form’. See South West Africa (Ethiopia v South Africa) (Second Phase) [1966] icj Reports 6, 34 [49].
d’Aspremont, Formalism and the Sources 13.
Hart H.L.A., The Concept of Law (3rd ed., Oxford: 2012) 94.
See Besson S., “Theorizing the Sources of International Law”, in Besson S. – Tasioulas J. (eds.), The Philosophy of International Law, (Oxford: 2010)163, 169–170; d’Aspremont, Formalism and the Sources 13; Wolfrum R., “Sources of International Law”, in Peters A. (ed.), Max Planck Encyclopedia of Public International Law (vol ix, Oxford: 2012) para. 6 (online at 6 June 2023).
Jennings R. – Watts A., Oppenheim’s International Law (9th ed., vol 1. London: 1996) 23.
Koskenniemi M., From Apology to Utopia. The Structure of International Legal Argument (rev. ed., Cambridge: 2005) 306.
Neff S.C., Justice Among Nations. A History of International Law (Cambridge, Massachusetts: 2014) 356. It needs, however, to be stressed that the influence of the pcij’s decisions on the development of international law were different in particular periods of its activity. This is well shown in Spiermann O., International Legal Argument in the Permanent Court of International Justice. The Rise of the International Judiciary (Cambridge: 2005) 132–133. It is not unfounded that Spiermann most appreciates the pcij’s decisions at the time of Max Huber’s presidency (1924–1931). A similar opinion was expressed, when the pcij still existed, by its long-time secretary, and then a judge in the final period of the Court’s activity, Ake Hammarskjöld. He wrote: ‘During the first years of its existence, the Court displayed a tendency to discuss and to give its views on most of the important questions of principle which arose in the cases submitted to it because it held that to contribute in this way to the restatement of international law was not the least important of its tasks. Subsequently, however, and, curiously enough, more particularly after 1930 […] the tendency has rather been, following the example of municipal tribunals, to avoid pronouncing upon questions the solution of which does not appear to be indispensable for the decision of the case’. Hammarskjöld A., “The Permanent Court of International Justice and the Development of International Law”, International Affairs 14 (1935) 799.
Spiermann, International Legal Argument 175. See also Barbara Stępień’s contribution to this volume, in particular, her remarks on internationalization of canals.
Ibid, 185.
Ibid, 181. See also ibid, 177.
See Chapter 5 by Władysław Czapliński in this volume.
The Case of the ss “Lotus” [1927] pcij Ser A No 10 at 18.
Rasulov A., “The Doctrine of Sources in the Discourse of the Permanent Court of International Justice”, in Tams Ch.J. – Fitzmaurice M. (eds), Legacies of the Permanent Court of International Justice (Leyden-Boston: 2013) 271, 304.
Ibid.
Ibid, 282, 299–302, 304.
The Author thanks the anonymous Reviewer of the book for pointing this out.
Spiermann, International Legal Argument 185.
The s.s. “Wimbledon”, Documents of the Written Procedure [1923] pcij Ser C No 3 (Additional Volume), 1.
The s.s. “Wimbledon”, Documents of the Written Procedure [1923] pcij Ser C No 3 (Additional Volume), 40.
Ibid.
Wimbledon, 21, 22.
Ibid, 22.
Ibid, 23–24.
Ibid, 29, 30.
Ibid, 33.
International Law Commission, Report of the Study Group of the International Law Commission, Conclusions of the Work of the Study Group, Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, Fifty-eighth session, Geneva, 1 May-9 June and 3 July-11 August 2006, a/cn.4/l.702 18 July 2006, para 2(10) note 11, at 10.
d’Argent, “Sources and the Legality” 545.
Wimbledon, 25.
Hudson M.O., Progress in International Organization (Stanford: 1932) 73–74.
Weinberger S., “The Wimbledon Paradox and the World Court: Confronting Inevitable Conflicts between Conventional and Customary International Law”, Emory International Law Review 10 (1996) 397.
Ibid, 425.
Ibid, 399, 436.
Ibid, 399.
Ibid, 434–435.
But cf. Verzijl J.H.H., The Jurisprudence of the World Court. A Case by Case Commentary. Vol i: The Permanent Court of International Justice (1922–1940) (Leyden: 1965) 43 (arguing that ‘for the appreciation of the Wimbledon case it is unnecessary to enter into the difficult but extremely interesting questions as to the relation between general neutrality and special treaty obligations’). As an arbitrator in the Georges Pinson case, Verzijl seemed to present a different proposition: ‘Every international convention must be deemed tacitly to refer to general principles of international law for all questions which it does not itself resolve in express terms and in a different way’, Georges Pinson (France) v. United Mexican States, 19 October 1928, Reports of International Arbitral Awards, Vol V, 327–466.
Simma and Alston speaking of an “identity crisis” of customary law argued persuasively that while the Permanent Court, in the process of identifying rules of customary law had paid attention to practice, its successor emphasized the importance of opinio juris, which is particularly noticeable in the Nicaragua judgment. Simma B.-Alston P., “The Sources of Human Rights Law: Custom, Jus Cogens, and General Principles”, Australian Year Book of International Law 12 (1989) 82, 88, 97, 104.
Wimbledon, 28. For critical comment see D’Amato A., The Concept of Custom in International Law (Ithaca N.Y.: 1971) 118–119; Weinberger, “The Wimbledon Paradox” 432. Cf. Hudson M.O., The Permanent Court of International Justice 1920–1943 (New York: 1943) 655, 657; Wolfke K., Custom in Present International Law (Wrocław: 1961) 41.
Wimbledon, 26.
Spiermann O., “History of Article 38 of the Statute of the International Court of Justice: ‘A Purely Platonic Discussion’?”, in Besson – Aspremont de (eds.) The Oxford Handbook of the Sources 172–173.
See Kwiecień R., “The Permanent Court of International Justice and the Constitutional Dimension of International Law: From Expectations to Reality”, in Tams – Fitzmaurice (eds.), Legacies of the Permanent Court of International Justice 361.
Paulus A.L., “The International Legal System as a Constitution”, in Dunoff J.L. – Trachtman J.P. (eds.) Ruling the World? Constitutionalism, International Law, and Global Governance (Cambridge: 2009) 69, 75.
Brierly J.L., “Shortcomings of International Law”, in Brierly J.L., The Basis of Obligations in International Law and Other Papers (Oxford: 1958) 75.
Ibid. See also Deryng A., Główne tendencje rozwojowe prawa narodów w świetle orzecznictwa Stałego Trybunału Sprawiedliwości Międzynarodowej [The Principal Trends in the Development of the Law of Nations under the Jurisprudence of the Permanent Court of International Justice] (Lwów: 1932) 106–107 (claiming that the interpretation of treaty law on the international canals given in the Wimbledon decision had the effect of changing particular treaty rules into generally bindings rules on the legal regime of the international canals).
Sørensen M., Les sources du droit international. Etude sur la Jurisprudence de la Cour Permamente de Justice Internationale (Copenhague: 1946) 57.
Ibid, 252–253.
Lauterpacht H., The Development of International Law by the International Court (New York: 1958) 392–393.
Ibid, 29.
Wimbledon, 21, 22.
Ibid, 25.
Ibid, 28.
See above note 41 and Spiermann, International Legal Argument 184 (claiming that ‘it can hardly justify a general theory of international canals, as the Permanent Court appeared to have in mind only the conflict between Article 380 of the Versailles Treaty and principles of neutrality’). But cf. Verzijl, The Jurisprudence of the World Court 44–45.
There were only four cases before the pcij where a judge voted against his own State. However, three of them, except the Wimbledon, were unanimously decided. See Grewe W.G., Epochen der Völkerrechtsgeschichte (2. Auflage, Baden-Baden: 1988) 723 (The Epochs of International Law, trans. Byers M. (Berlin: 2000) 615); Hudson M.O., The Permanent Court of International Justice: A Treatise (New York: 1934) 337–338.
Wimbledon, Dissenting Opinion by M.M. Anzilotti and Huber, 36. See Article 8 of the Barcelona Statute on Freedom of Transit, 20 April 1921, vol. 7 League of Nations Treaty Series No. 171, 26 (‘This Statute does not prescribe the rights and duties of belligerents and neutrals in time of war. The Statute shall, however, continue in force in time of war so far as such rights and duties permit’).
Wimbledon, Dissenting Opinion by M. Schücking, 43–44.
Ibid, 47.
See Chapter 7 by Michał Kowalski in this volume.
Lauterpacht, The Development of International Law 24.
See generally Venzke I., How Interpretation Makes International Law. On Semantic Change and Normative Twists (Oxford: 2012).
Article 31(3)(c) of the Vienna Convention on the Law of Treaties, 1155 United Nations Treaty Series 331.
On the origins of this provision of Article 31(3)(c) of the vclt see Gardiner R., Treaty Interpretation (Oxford: 2010) 256–259; McLachlan C., “The Principle of Systemic Integration and Article 31(3)(c) of the Vienna Convention”, International and Comparative Law Quarterly 54 (2005) 279, 290–293; Zabalza G.O., The Principle of Systemic Integration. Towards a Coherent International Legal Order (Zurich: 2012) 211–233.
Wimbledon, 25.
Gowlland-Debbas V., “The Role of the International Court of Justice in the Development of the Contemporary Law of Treaties”, in Tams Ch.J. – Sloan J. (eds.), The Development of International Law by the International Court of Justice (Oxford: 2013) 25, 35.
Wimbledon, Dissenting Opinion by M.M. Anzilotti and Huber, 35.
Ibid.
Ibid, 36.
Ibid.
Ibid, 37.
Ibid, 38.
Wimbledon, Dissenting Opinion by M. Schücking, 47.
Wimbledon, 21, 22.
Ibid, 24.
McNair A.D., The Law of Treaties. British Practice and Opinions (Oxford: 1938) 175–176 (emphasizes in original). See also ibid his remarks on ‘implied terms and conditions’ under the Wimbledon judgment, at 233 (n 2), 245.
Wimbledon, 22.
Wimbledon, 24–5. See Wittich S., “The Permanent Court of International Justice and the Modern International Law of Treaties”, in Tams – Fitzmaurice (eds.), Legacies of the Permanent Court 89, 107–108 (claiming that the Permanent Court in its jurisprudence gave ‘preference to the objective textual approach. This is not to say that the Court ignored the common intention of the parties. But first of all, such intention must in any event be reflected in the terms of the treaty’).
See e.g. Application of the International Convention on the Elimination of All Forms of Racial Discrimination (Qatar v United Arab Emirates) (Preliminary Objections) icj Reports 2021, 71, 98, para. 81 (repeating after its previous decisions: ‘[i]nterpretation must be based above all upon the text of the treaty’).
See e.g. Lauterpacht H., The Development of International Law by the Permanent Court (Oxford: 1934) 69; Lauterpacht H, “Restrictive Interpretation and the Principle of Effectiveness in the Interpretation of Treaties”, British Yearbook of International Law 26 (1949) 48; Ehrlich L., “L’interpretation des traités”, Recueil des Cours 24 (1928) 1, 60, 92, 132–133, 136–137; Hudson, The Permanent Court 649–650 (who put on the top of the elements of interpretation under the jurisprudence of the pcij the concept of ‘authentic interpretation’, that is, the interpretation of a treaty on which all parties to it were agreed). Cf. Collette J., Principes de droit des gens dans la jurisprudence de la Cour Permanente de Justice Internationale (Paris: 1932) 73; Gardiner, Treaty Interpretation 59; Verzijl, The Jurisprudence of the World Court 44–45.
See Wimbledon, 23.
Ibid, 24.
See on the doctrine of ‘plain terms’ above note 77.
Wittich, “The Permanent Court” 100.
Ibid, 103.
Wimbledon, 25. See critical comments by Klabbers J., “Clinching the Concept of Sovereignty: Wimbledon Redux”, Austrian Review of International and European Law 3 (1998) 345 and Chapter 5 in this book.
See Ehrlich, “L’interpretation des traités” 45, 69; Lauterpacht, The Development of International Law 302–303; Sørensen, Les sources du droit international 229. But cf. Crawford, Chance, Order, Change 91–92 (arguing that in the Wimbledon case the Court ‘interpreted the provisions in accordance with their ordinary meaning but conceded that in case of doubt the interpretation least restrictive of sovereignty would prevail’ and commenting that ‘[t]oday an international court will not start with such a presumption in interpreting a treaty’). Cf. also Wittich, “The Permanent Court” 105.
Wimbledon, 25.
Cf. Lauterpacht, The Development of International Law 393.
See Higgins R., “A Babel of Judicial Voices? Ruminations from the Bench”, International and Comparative Law Quarterly 55 (2006) 791, 803 (claiming that each treaty regime is a special regime because each of them consists of own substantive primary rules).
See Article 48(1)(b) of The Articles of the ilc: Responsibility of States for Internationally Wrongful Acts, Annex to General Assembly resolution 56/83 of 12 December 2001, and corrected by document A/56/49 (Vol. I)/Corr.4.
Weil P., “Towards Relative Normativity in International Law?”, American Journal of International Law 77 (1983) 413. See also Fastenrath U., “Relative Normativity in International Law”, European Journal of International Law 4 (1993) 305; Goldmann M, “Relative Normativity”, in d’Aspremont J. – Singh S. (eds.), Concepts for International Law. Contributions to Disciplinary Thought (Cheltenham: 2019) 740; Koskenniemi M., “Hierarchy in International Law: A Sketch”, European Journal of International Law 8 (1997) 566; Shelton D., “International Law and ‘Relative Normativity’”, in Evans M.D. (ed.), International Law (3rd ed., Oxford: 2010) 141; Weiler J.H.H. – Paulus A.L., “The Structure of Change in International Law or Is There a Hierarchy of Norms in International Law?” European Journal of International Law 8 (1997) 545.
On the relationship between sources and the normative hierarchy in international law, see, e.g. de Wet E., “Sources and the Hierarchy of International Law: The Place of Peremptory Norms and Article 103 of the UN Charter within the Sources of International Law”, in Besson – d’Aspremont (eds.), The Oxford Handbook of the Sources of International Law 625.
See on ‘the principle of harmonization’, International Law Commission, Report of the Study Group of the International Law Commission, Conclusions of the Work of the Study Group: Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, para. 1(4), at 8.
See Weil, “Towards Relative Normativity” 416, 418, 431–433, 440–441.
See esp. Fastenrath, “Relative Normativity” 331–340; Shelton, “International Law and ‘Relative Normativity’” 141–144.
Fastenrath, “Relative Normativity” 306.
Shelton, “International Law and ‘Relative Normativity’” 143.
Payment in Gold of Brazilian Federal Loans Contracted in France (n 3) at 124.
Shelton, “International Law and ‘Relative Normativity’” 142. See also Shelton D., “Normative Hierarchy in International Law”, American Journal of International Law 100 (2006) 291.
Besson, “Theorizing the Sources of International Law” 183–184; Fitzmaurice M., “The History of Article 38 of the Statute of the International Court of Justice. The Journey from the Past to the Present”, in Besson – Aspremont de (eds.), The Oxford Handbook of the Sources of International Law 179, 187–188. See also Part iii.A of this chapter on the principle of systemic integration.
The International Law Commission has used the Wimbledon case as evidence of the treaty special regime relating to a special subject matter. See Report of the Study Group of the International Law Commission, Conclusions of the Work of the Study Group, Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, para 12 (note 14) at 12. See also Borgen Ch.J., “Treaty Conflicts and Normative Fragmentation”, in Hollis D.B. (ed.), The Oxford Guide to Treaties (Oxford: 2014) 448, 467.
Orakhelashvili A., Peremptory Norms in International Law (Oxford: 2007) 42.
Orakhelashvili, Peremptory Norms 166 claims that in the Wimbledon case general international law was ‘irrelevant’. See also Villiger M.E., Customary International Law and Treaties. A Study of Their Interactions and Interrelations with Special Consideration of the 1969 Vienna Convention on the Law of Treaties (Dordrecht-Boston-Lancaster: 1985) 35, note 353 (who claimed, referring to the Wimbledon case, that ‘the pcij occasionally preferred a treaty rule to a conflicting customary rule’).
Advisory Committee of Jurists, Procès-verbaux of the Proceedings of the Advisory Committee of Jurists, June 16-July 24 1920, with Annexes (The Hague: 1920) 264 (Descamps). For comments see Spiermann, “History of Article 38” 171–173.
Spiermann, “History of Article 38” 168.
Saunders I., General Principles as a Source of International Law. Art 38(1)(c) of the Statute of the International Court of Justice (Oxford: 2021) 57. See also Cheng B., General Principles of Law as Applied by International Courts and Tribunals (London: 1958) 29–30.
Wimbledon, 22.
Ibid, 30.
See International Law Commission, Report of the Study Group of the International Law Commission, Conclusions of the Work of the Study Group on the Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, para. 2(10), at 10.
Wimbledon, Dissenting Opinion by M. Schücking, 43–44. See also Wimbledon, Dissenting Opinion by M.M. Anzilotti and Huber, 36.
Wimbledon, 28.
See e.g. Lauterpacht, The Development of International Law 24 (writing ‘what the Court actually had in mind was opinions of writers’); Sørensen, Les sources du droit international 181 (recognizing it as des opinions doctrinales); Wolfke, Custom 151 (referring to ‘opinions of publicists’ or ‘writers’; but see ibid, 41).
Hudson, International Tribunals 107–108.
Legality of the Threat or Use of Nuclear Weapons, Dissenting Opinion of Judge Higgins, icj Reports 1996, par. 7, at 584. Higgins further claimed: ‘Nor is the situation changed by any suggestion that the problem is as much one as “antimony” or clashes between various elements in the law as much as alleged “vagueness” in the law. Even were there such an “antimony” (which, as I have indicated above, I doubt), the judge’s role is precisely to decide which of two or more competing norms is applicable in the particular circumstances’ (ibid, par. 40, at 592).
Wimbledon, 25.
See Barcelona Traction, Light and Power Company, Limited, Judgment, icj Reports 1970, 3, 32, paras. 33–34.
See Chapter 4 by Malgosia Fitzmaurice and Agnes Rydberg in this volume.
Baxter R., “Treaties and Custom”, Recueil des Cours 129 (1970) 25, 64. See comments on this ‘paradox’, Crawford, Chance, Order, Change 115–118, 134–146.
Brölmann C., “Law-Making Treaties: Form and Function in International Law”, Nordic Journal of International Law 74(3–4) (2005) 383, 400.
See Fitzmaurice G.G., “Some Problems Regarding the Formal Sources of International Law” in Asbeck F.M. Van et al (eds.), Symbolae Verzijl. Présentés au Professeur J.H. Verzijl à L’occasion de Son lxx-ième Anniversaire (Leyden: 1958) 153, 157; Jennings – Watts, Oppenheim’s International Law 24–25, 31; Besson, “Theorizing the Sources of International Law” 168–169; Brölmann, “Law-Making Treaties” 398; Condorelli L., “Customary International Law: The Yesterday, Today, and Tomorrow of General International Law” in Cassese A. (ed.), Realizing Utopia. The Future of International Law (Oxford: 2012) 149–152.
Crawford, Chance, Order, Change 139. See also Brölmann, “Law-Making Treaties” 383; Charney J., “Universal International Law”, American Journal of International Law 87 (1993) 529, 551; Dinstein Y., “The Interaction between Customary International Law and Treaties” 322 (2006) Recueil des Cours 243, 377–378; Kwiecień R., “The Formal Sources of International Law, the Relationship between Treaties and Custom, and the International Law-Making Process”, Australian Year Book of International Law 40 (2022) 46, 62–65. But see contra, e.g., Dissenting Opinion by Judge Alvarez to the Reservations to the Convention on Prevention and Punishment of the Crime of Genocide Advisory Opinion, [1951] icj Rep 15, 53 (‘Reservations’). Judge Alvarez claimed that law-making treaties ‘signed by a great majority of States ought to be binding upon the others, even though they have not expressly accepted them’. Likewise D’Amato A., “Treaties as a Source of General Rules of International Law”, Harvard International Law Club Journal 3(2) (1962) 1, 12–17.
See Report of the Study Group of the International Law Commission, Conclusions of the Work of the Study Group on Fragmentation of International Law: Difficulties Arising from the Diversification and Expansion of International Law, para 1(1), at 7.
See esp. Reservations to the Convention on Genocide, Advisory Opinion, icj Reports 1951, 15, 23–24, 53; North Sea Continental Shelf Cases (Federal Republic of Germany/Denmark; Federal Republic of Germany/Netherlands) Judgment, icj Reports 1969, 3, 43, para. 76; Continental Shelf (Libyan Arab Jamahiryia/Malta) Judgment, icj Reports 1985, 13, 30, para. 27; Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States of America), Merits, Judgment, icj Reports 1986, 14, 93–96, para. 175–179.
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pcij
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Case of thes.s.“Wimbledon” [1923] pcij Ser A No 1.
The Case of thess“Lotus” [1927] pcij Ser A No 10.
Thes.s.“Wimbledon”, Documents of the Written Procedure [1923] pcij Ser C No 3 (Additional Volume), 1.
Thes.s.“Wimbledon”, Documents of the Written Procedure [1923] pcij Ser C No 3 (Additional Volume), 40.
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icj
Application of the International Convention on the Elimination of All Forms of Racial Discrimination (Qatar v United Arab Emirates) (Preliminary Objections) icj Reports 2021, 71.
Barcelona Traction, Light and Power Company, Limited, Judgment, icj Reports 1970, 3.
Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, icj Reports 1996, 226.
Legality of the Threat or Use of Nuclear Weapons, Dissenting Opinion of Judge Higgins, icj Reports 1996.
North Sea Continental Shelf Cases (Federal Republic of Germany/Denmark; Federal Republic of Germany/Netherlands) Judgment, icj Reports 1969, 3.
Reservations to the Convention on Genocide, Advisory Opinion, icj Reports 1951, 15. Reservations to the Convention on Prevention and Punishment of the Crime of Genocide Advisory Opinion, Dissenting Opinion by Judge Alvarez, icj Reports 1951 .
South West Africa (Ethiopia v South Africa) (Second Phase), icj Reports 1966, 6.
Other Sources
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