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

account any relevant rules of international law when examining questions concerning its

jurisdiction and, consequently, determine State responsibility in conformity with the governing

principles of international law, although it must remain mindful of the Convention’s special

character as a human rights treaty. The Convention should be interpreted as far as possible in

harmony with other principles of international law of which it forms part”.

Similarly in Korea - Measures Affecting Government Procurement (19 January 2000)

WT/DS163/R, para. 7.96, the Appellate Body of the WTO noted the relationship between the

WTO Covered agreements and general international law as follows: “We take note that

Article 3 (2) of the DSU requires that we seek within the context of a particular dispute to clarify

the existing provisions of the WTO agreements in accordance with customary international law

rules of interpretation of public international law. However, the relationship of the WTO

agreements to customary international law is broader than this. Customary international law

applies generally to the economic relations between WTO members. Such international law

applies to the extent that the WTO treaty agreements do not ‘contract out’ from it. To put it

another way, to the extent that there is no conflict or inconsistency, or an expression in a covered

WTO agreement that applies differently, we are of the view that the customary rules of

international law apply to the WTO treaties and to the process of treaty formation under the

WTO.”

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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. 16

(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; 17

16 In the Oil Platforms case (Iran v. United States of America) (Merits) I.C.J. Reports 2003,

at para. 41, the Court spoke of the relations between a bilateral treaty and general international

law by reference to article 31 (3) (c) as follows: “Moreover, under the general rules of treaty

interpretation, as reflected in the 1969 Vienna Convention on the Law of Treaties, interpretation

must take into account ‘any relevant rules of international law applicable in the relations

between the parties’ (Article 31, paragraph 3 (c)). The Court cannot accept that Article XX,

paragraph 1 (d), of the 1955 Treaty was intended to operate wholly independently of the relevant

rules of international law … The application of the relevant rules of international law relating

to this question thus forms an integral part of the task of interpretation entrusted to the Court

by … the 1955 Treaty.”

17 Georges Pinson case (France/United Mexican States) Award of 13 April 1928, UNRIAA,

vol. V, p. 422. It was noted that parties are taken to refer to general principles of international

law for questions which the treaty does not itself resolve in express terms or in a different way.

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(b) In entering into treaty obligations, the parties do not intend to act

inconsistently with generally recognized principles of international law. 18

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

18 In the Case concerning the Right of Passage over Indian Territory (Portugal v. India)

(Preliminary Objections) I.C.J. Reports 1957, p. 125 at p. 142, the Court stated: “It is a rule of

interpretation that a text emanating from a government must, in principle, be interpreted as

producing and as intended to produce effects in accordance with existing law and not in violation

of it.”

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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. 19

(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; 20

19 The traditional rule was stated by Judge Huber in the Island of Palmas case

(the Netherlands/United States of America) Award of 4 April 1928, UNRIAA, vol. II, p. 829,

at p. 845, in the context of territorial claims: “… a juridical fact must be appreciated in the light

of the law contemporary with it, and not the law in force at the time when a dispute in regard to

it arises or fails to be settled … The same principle which subjects the act creative of a right to

the law in force at the time the right arises, demands that the existence of the right, in other

words, its continued manifestations, shall follow the conditions required by the evolution of

law”.

20 In the Case concerning the Gabč ikovo-Nagymaros Project (Hungary v. Slovakia)

I.C.J. Reports 1997, p. 7 at pp. 67-68, para. 112, the Court observed: “By inserting these

evolving provisions in the Treaty, the parties recognized the potential necessity to adapt the

Project. Consequently, the Treaty is not static, and is open to adapt to emerging norms of

international law. By means of Articles 15 and 19, new environmental norms can be

incorporated in the Joint Contractual Plan.”

In the Arbitration regarding the Iron Rhine (IJZEREN RIJN) Railway (Belgium v.

Netherlands) of 24 May 2005, a conceptual or generic term was not in issue but a new technical

development relating to the operation and capacity of a railway. Evolutive interpretation was

used to ensure the effective application of the treaty in terms of its object and purpose. The

Tribunal observed in paragraphs 82 and 83: “The object and purpose of the 1839 Treaty of

Separation was to resolve the many difficult problems complicating a stable separation of

Belgium and the Netherlands: that of Article XII was to provide for transport links from

Belgium to Germany, across a route designated by the 1842 Boundary Treaty. This object was

not for a fixed duration and its purpose was ‘commercial communication’. It necessarily

follows, even in the absence of specific wording, that such works, going beyond restoration to

previous functionality, as might from time to time be necessary or desirable for contemporary

commerciality, would remain a concomitant of the right of transit that Belgium would be able to

request. That being so, the entirety of Article XII, with its careful balance of the rights and

obligations of the Parties, remains in principle applicable to the adaptation and modernisation

requested by Belgium”, Text of award available on > https://www.pca-cpa.org>. (last visited

on 14 July 2006).

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(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. 21