Conclusions of the work of the Study Group on the Fragmentation of International Law: Difficulties arising from the Diversification and Expansion of International Law
(1) International law as a legal system. 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. Norms may thus exist at higher and lower hierarchical levels, their formulation may involve greater or lesser generality and specificity and their validity may date back to earlier or later moments in time.
(2) In applying international law, it is often necessary to determine the precise relationship between two or more rules and principles that are both valid and applicable in respect of a situation.1 For that purpose the relevant relationships fall into two general types:
Relationships of interpretation. This is the case where one norm assists in the interpretation of another. A norm may assist in the interpretation of another norm for example as an application, clarification, updating, or modification of the latter. In such situation, both norms are applied in conjunction.
Relationships of conflict. This is the case where two norms that are both valid and applicable point to incompatible decisions so that a choice must be made between them. The basic rules concerning the resolution of normative conflicts are to be found in the VCLT.
(3) The VCLT. When seeking to determine the relationship of two or more norms to each other, the norms should be interpreted in accordance with or analogously to the VCLT and especially the provisions in its articles 31-33 having to do with the interpretation of treaties.
(4) The principle of harmonization. It is a generally accepted 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 compatible obligations.
2. The maxim lex specialis derogat legi generali
(5) General principle. The maxim lex specialis derogat legi generali is a generally accepted technique of interpretation and conflict resolution in international law. It suggests that whenever two or more norms deal with the same subject matter, priority should be given to the norm that is more specific. The principle may be applicable in several contexts: between provisions within a single treaty, between provisions within two or more treaties, between a treaty and a non-treaty standard, as well as between two non-treaty standards.2 The source of the norm (whether treaty, custom or general principle of law) is not decisive for the determination of the more specific standard. However, in practice treaties often act as lex specialis by reference to the relevant customary law and general principles.3
(6) Contextual appreciation. The relationship between the lex specialis maxim and other norms of interpretation or conflict solution cannot be determined in a general way. Which consideration should be predominant - i.e. whether it is the speciality or the time of emergence of the norm - should be decided contextually.
(7) Rationale of the principle. That special law has priority over general law is justified by the fact that such special law, being more concrete, often takes better account of the particular features of the context in which it is to be applied than any applicable general law. Its application may also often create a more equitable result and it may often better reflect the intent of the legal subjects.
(8) Functions of lex specialis. Most of international law is dispositive. This means that special law may be used to apply, clarify, update or modify as well as set aside general law.
(9) The effect of lex specialis on general law. The application of the special law does not normally extinguish the relevant general law.4 That general law will remain valid and applicable and will, in accordance with the principle of harmonization under conclusion (4) above, continue to give direction for the interpretation and application of the relevant special law and will become fully applicable in situations not provided for by the latter.5
(10) Particular types of general law. Certain types of general law6 may not, however, be derogated from by special law. Jus cogens is expressly non-derogable as set out in conclusions (32), (33), (40) and (41), below.7 Moreover, there are other considerations that may provide a reason for concluding that a general law would prevail in which case the lex specialis presumption may not apply. These include the following:
Whether such prevalence may be inferred from the form or the nature of the general law or intent of the parties, wherever applicable;
Whether the application of the special law might frustrate the purpose of the general law;
Whether third party beneficiaries may be negatively affected by the special law; and
Whether the balance of rights and obligations, established in the general law would be negatively affected by the special law.
3. Special (self-contained) regimes
(11) Special (“self-contained”) regimes as lex specialis. A group of rules and principles concerned with a particular subject matter may form a special regime (“Self contained regime”) and be applicable as lex specialis. Such special regimes often have their own institutions to administer the relevant rules.
(12) Three types of special regime may be distinguished:
Sometimes violation of a particular group of (primary) rules is accompanied by a special set of (secondary) rules concerning breach and reactions to breach. This is the main case provided for under article 55 of the articles on Responsibility of States for internationally wrongful acts.8
Sometimes, however, a special regime is formed by a set of special rules, including rights and obligations, relating to a special subject matter. Such rules may concern a geographical area (e.g. a treaty on the protection of a particular river) or some substantive matter (e.g. a treaty on the regulation of the uses of a particular weapon). Such a special regime may emerge on the basis of a single treaty, several treaties, or treaty and treaties plus non-treaty developments (subsequent practice or customary law).9
Finally, sometimes all the rules and principles that regulate a certain problem area are collected together so as to express a “special regime”. Expressions such as “law of the sea”, “humanitarian law”, “human rights law”, “environmental law” and “trade law”, etc. give expression to some such regimes. For interpretative purposes, such regimes may often be considered in their entirety.
(13) Effect of the “speciality” of a regime. The significance of a special regime often lies in the way its norms express a unified object and purpose. Thus, their interpretation and application should, to the extent possible, reflect that object and purpose.
(14) The relationship between special regimes and general international law. A special regime may prevail over general law under the same conditions as lex specialis generally (see conclusions (8) and (10) above).
(15) The role of general law in special regimes: Gap-filling. The scope of special laws is by definition narrower than that of general laws. It will thus frequently be the case that a matter not regulated by special law will arise in the institutions charged to administer it. In such cases, the relevant general law will apply.10
(16) The role of general law in special regimes: Failure of special regimes. Special regimes or the institutions set up by them may fail. Failure might be inferred when the special laws have no reasonable prospect of appropriately addressing the objectives for which they were enacted. It could be manifested, for example, by the failure of the regime’s institutions to fulfil the purposes allotted to them, persistent non-compliance by one or several of the parties, desuetude, withdrawal by parties instrumental for the regime, among other causes. Whether a regime has “failed” in this sense, however, would have to be assessed above all by an interpretation of its constitutional instruments. In the event of failure, the relevant general law becomes applicable.
4. Article 31 (3) (c) VCLT
(17) Systemic integration. Article 31 (3) (c) VCLT provides one means within the framework of the VCLT, through which relationships of interpretation (referred to in conclusion (2) above) may be applied. It requires the interpreter of a treaty to take into account “any relevant rules of international law applicable in relations between the parties”. The article gives expression to the objective of “systemic integration” according to which, whatever their subject matter, treaties are a creation of the international legal system and their operation is predicated upon that fact.
(18) Interpretation as integration in the system. Systemic integration governs all treaty interpretation, the other relevant aspects of which are set out in the other paragraphs of articles 31-32 VCLT. These paragraphs describe a process of legal reasoning, in which particular elements will have greater or less relevance depending upon the nature of the treaty provisions in the context of interpretation. In many cases, the issue of interpretation will be capable of resolution with the framework of the treaty itself. Article 31 (3) (c) deals with the case where material sources external to the treaty are relevant in its interpretation. These may include other treaties, customary rules or general principles of law.11
(19) Application of systemic integration. Where a treaty functions in the context of other agreements, the objective of systemic integration will apply as a presumption with both positive and negative aspects:
(a) The parties are taken to refer to customary international law and general principles of law for all questions which the treaty does not itself resolve in express terms;12
(b) In entering into treaty obligations, the parties do not intend to act inconsistently with generally recognized principles of international law.13
Of course, if any other result is indicated by ordinary methods of treaty interpretation that should be given effect, unless the relevant principle were part of jus cogens.
(20) Application of custom and general principles of law. Customary international law and general principles of law are of particular relevance to the interpretation of a treaty under article 31 (3) (c) especially where:
(a) The treaty rule is unclear or open-textured;
(b) The terms used in the treaty have a recognized meaning in customary international law or under general principles of law;
(c) The treaty is silent on the applicable law and it is necessary for the interpreter, applying the presumption in conclusion (19) (a) above, to look for rules developed in another part of international law to resolve the point.
(21) Application of other treaty rules. Article 31 (3) (c) also requires the interpreter to consider other treaty-based rules so as to arrive at a consistent meaning. Such other rules are of particular relevance where parties to the treaty under interpretation are also parties to the other treaty, where the treaty rule has passed into or expresses customary international law or where they provide evidence of the common understanding of the parties as to the object and purpose of the treaty under interpretation or as to the meaning of a particular term.
(22) Inter-temporality. International law is a dynamic legal system. A treaty may convey whether in applying article 31 (3) (c) the interpreter should refer only to rules of international law in force at the time of the conclusion of the treaty or may also take into account subsequent changes in the law. Moreover, the meaning of a treaty provision may also be affected by subsequent developments, especially where there are subsequent developments in customary law and general principles of law.14
(23) Open or evolving concepts. Rules of international law subsequent to the treaty to be interpreted may be taken into account especially where the concepts used in the treaty are open or evolving. This is the case, in particular, where: (a) the concept is one which implies taking into account subsequent technical, economic or legal developments;15 (b) the concept sets up an obligation for further progressive development for the parties; or (c) the concept has a very general nature or is expressed in such general terms that it must take into account changing circumstances.16
5. Conflicts between successive norms
(24) Lex posterior derogat legi priori. According to article 30 VCLT, when all the parties to a treaty are also parties to an earlier treaty on the same subject, and the earlier treaty is not suspended or terminated, then it applies only to the extent its provisions are compatible with those of the later treaty. This is an expression of the principle according to which “later law supersedes earlier law”.
(25) Limits of the “lex posterior” principle. The applicability of the lex posterior principle is, however, limited. It cannot, for example, be automatically extended to the case where the parties to the subsequent treaty are not identical to the parties of the earlier treaty. In such cases, as provided in article 30 (4) VCLT, the State that is party to two incompatible treaties is bound vis à-vis both of its treaty parties separately. In case it cannot fulfil its obligations under both treaties, it risks being responsible for the breach of one of them unless the concerned parties agree otherwise. In such case, also article 60 VCLT may become applicable. The question which of the incompatible treaties should be implemented and the breach of which should attract State responsibility cannot be answered by a general rule.17 Conclusions (26)-(27) below lay out considerations that might then be taken into account.
(26) The distinction between treaty provisions that belong to the same “regime” and provisions in different “regimes”. The lex posterior principle is at its strongest in regard to conflicting or overlapping provisions that are part of treaties that are institutionally linked or otherwise intended to advance similar objectives (i.e. form part of the same regime). In case of conflicts or overlaps between treaties in different regimes, the question of which of them is later in time would not necessarily express any presumption of priority between them. Instead, States bound by the treaty obligations should try to implement them as far as possible with the view of mutual accommodation and in accordance with the principle of harmonization. However, the substantive rights of treaty parties or third party beneficiaries should not be undermined.
(27) Particular types of treaties or treaty provisions. The lex posterior presumption may not apply where the parties have intended otherwise, which may be inferred from the nature of the provisions or the relevant instruments, or from their object and purpose. The limitations that apply in respect of the lex specialis presumption in conclusion (10) may also be relevant with respect to the lex posterior.
(28) Settlement of disputes within and across regimes. Disputes between States involving conflicting treaty provisions should be normally resolved by negotiation between parties to the relevant treaties. However, when no negotiated solution is available, recourse ought to be had, where appropriate, to other available means of dispute settlement. When the conflict concerns provisions within a single regime (as defined in conclusion (26) above), then its resolution may be appropriate in the regime specific mechanism. However, when the conflict concerns provisions in treaties that are not part of the same regime, special attention should be given to the independence of the means of settlement chosen.
(29) Inter se agreements. The case of agreements to modify multilateral treaties by certain of the parties only (inter se agreements) is covered by article 41 VCLT. Such agreements are an often used technique for the more effective implementation of the original treaty between a limited number of treaty parties that are willing to take more effective or more far-reaching measures for the realization of the object and purpose of the original treaty. Inter se agreements may be concluded if this is provided for by the original treaty or it is not specifically prohibited and the agreement: “(i) does not affect the enjoyment by the other parties of their rights under the treaty or the performance of their obligations; (ii) does not relate to a provision, derogation from which is incompatible with the effective execution of the object and purpose of the treaty as a whole” (article 41 (1) (b) VCLT).
(30) Conflict clauses. When States enter into a treaty that might conflict with other treaties, they should aim to settle the relationship between such treaties by adopting appropriate conflict clauses. When adopting such clauses, it should be borne in mind that:
(a) They may not affect the rights of third parties;
(b) They should be as clear and specific as possible. In particular, they should be directed to specific provisions of the treaty and they should not undermine the object and purpose of the treaty;
(c) They should, as appropriate, be linked with means of dispute settlement.
6. Hierarchy in international law: Jus cogens, Obligations erga omnes,
Article 103 of the Charter of the United Nations
(31) Hierarchical relations between norms of international law. The main sources of international law (treaties, custom, general principles of law as laid out in Article 38 of the Statute of the International Court of Justice) are not in a hierarchical relationship inter se.18 Drawing analogies from the hierarchical nature of domestic legal system is not generally appropriate owing to the differences between the two systems. Nevertheless, some rules of international law are more important than other rules and for this reason enjoy a superior position or special status in the international legal system. This is sometimes expressed by the designation of some norms as “fundamental” or as expressive of “elementary considerations of humanity”19 or “intransgressible principles of international law”.20 What effect such designations may have is usually determined by the relevant context or instrument in which that designation appears.
(32) Recognized hierarchical relations by the substance of the rules: Jus cogens. A rule of international law may be superior to other rules on account of the importance of its content as well as the universal acceptance of its superiority. This is the case of peremptory norms of international law (jus cogens, Article 53 VCLT), that is, norms “accepted and recognized by the international community of States as a whole from which no derogation is permitted”.21
(33) The content of jus cogens. The most frequently cited examples of jus cogens norms are the prohibition of aggression, slavery and the slave trade, genocide, racial discrimination apartheid and torture, as well as basic rules of international humanitarian law applicable in armed conflict, and the right to self-determination.22 Also other rules may have a jus cogens character inasmuch as they are accepted and recognized by the international community of States as a whole as norms from which no derogation is permitted.
(34) Recognized hierarchical relations by virtue of a treaty provision: Article 103 of the Charter of the United Nations. A rule of international law may also be superior to other rules by virtue of a treaty provision. This is the case of Article 103 of the United Nations Charter by virtue of which “In the event of a conflict between the obligations of the Members of the United Nations under the … Charter and their obligations under any other international agreement, their obligations under the … Charter shall prevail.”
(35) The scope of Article 103 of the Charter. The scope of Article 103 extends not only to the Articles of the Charter but also to binding decisions made by United Nations organs such as the Security Council.23 Given the character of some Charter provisions, the constitutional character of the Charter and the established practice of States and United Nations organs, Charter obligations may also prevail over inconsistent customary international law.
(36) The status of the United Nations Charter. It is also recognized that the United Nations Charter itself enjoys special character owing to the fundamental nature of some of its norms, particularly its principles and purposes and its universal acceptance.24
(37) Rules specifying obligations owed to the international community as a whole: Obligations erga omnes. Some obligations enjoy a special status owing to the universal scope of their applicability. This is the case of obligations erga omnes, that is obligations of a State towards the international community as a whole. These rules concern all States and all States can be held to have a legal interest in the protection of the rights involved.25 Every State may invoke the responsibility of the State violating such obligations.26
(38) The relationship between jus cogens norms and obligations erga omnes. It is recognized that while all obligations established by jus cogens norms, as referred to in conclusion (33) above, also have the character of erga omnes obligations, the reverse is not necessarily true.27 Not all erga omnes obligations are established by peremptory norms of general international law. This is the case, for example, of certain obligations under “the principles and rules concerning the basic rights of the human person”,28 as well as of some obligations relating to the global commons.29
(39) Different approaches to the concept of obligations erga omnes. The concept of erga omnes obligations has also been used to refer to treaty obligations that a State owes to all other States parties (obligations erga omnes partes)30 or to non-party States as third party beneficiaries. In addition, issues of territorial status have frequently been addressed in erga omnes terms, referring to their opposability to all States.31 Thus, boundary and territorial treaties have been stated to “represent a legal reality which necessarily impinges upon third States, because they have effect erga omnes”.32
(40) The relationship between jus cogens and the obligations under the United Nations Charter. The United Nations Charter has been universally accepted by States and thus a conflict between jus cogens norms and Charter obligations is difficult to contemplate. In any case, according to Article 24 (2) of the Charter, the Security Council shall act in accordance with the Purposes and Principles of the United Nations which include norms that have been subsequently treated as jus cogens.
(41) The operation and effect of jus cogens norms and Article 103 of the Charter:
(a) A rule conflicting with a norm of jus cogens becomes thereby ipso facto void;
(b) A rule conflicting with Article 103 of the United Nations Charter becomes inapplicable as a result of such conflict and to the extent of such conflict.
(42) Hierarchy and the principle of harmonization. Conflicts between rules of international law should be resolved in accordance with the principle of harmonization, as laid out in conclusion (4) above. In the case of conflict between one of the hierarchically superior norms referred to in this section and another norm of international law, the latter should, to the extent possible, be interpreted in a manner consistent with the former. In case this is not possible, the superior norm will prevail.