with regard to the interpretation of treaties
"A treaty shall be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose." (Article 31 (1); here again, as in the Articles 18, 19, 20 (2), 41 (1)(b)(ii) and 58 (1)(b)(ii), we find again the vague concept of "object and purpose of a treaty").
The context includes, in addition to the treaty text itself, the preamble and the annexes as well as other agreements and documents which are considered by the parties as being instruments related to the treaty (Article 31 (2)). Furthermore, any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation has to be taken into account, too.
According to the "Appellate Body", the highest dispute settlement organ of the World Trade Organization (WTO), the context of a legal instrument is also constituted by the other treaties its parties adhere to. Hence, in the case concerning "Standards for Reformulated and Conventional Gasoline" the Appellate Body explained that the Marrakesh Agreement Establishing the World Trade Organization (the "WTO Agreement") "is not to be read in clinical isolation from public international law". That means, in particular, that the trade provisions of the WTO Agreement have also to be interpreted in the light of conventions for the protection of the environment, provided that they are in force between the States Parties of the WTO Agreement.
Finally, there are supplementary means of interpretation as, for instance, the preparatory work of the treaty (so called "travaux préparatoires") and the circumstances of its conclusion (Article 32).
A specificity of international conventions lies in the fact that they are authenticated in several languages (see Article 33). With regard to treaties concluded under the auspices of the United Nations, these languages are regulary: Arabic, Chinese, English, French, Spanish and Russian.
The terms of the treaty are presumed to have the same meaning in each authentic text (Article 33 (3)). In the case of several Protocols to the Convention for the Protection of the
The LaGrand case revealed a divergence between the equally authentic English and Fench versions of Article 41 of the Statute of the International Court of Justice. Hence, the Court had to examine the object and purpose of the Statute together with the context of Article 41. In this way, the Court, in its judgement of
Specific application of the good faith principle (bona fide)
A State is entitled to invoke a deficiency of intention if the other States
Parties knew that its consent had been expressed in manifest violation of a fundamental rule of internal law regarding competence to conclude treaties. In this case, the other parties cannot pretend bona fide that the State genuinely wished to be bound by the treaty in question. According to Article 46 (2), a violation is manifest if it would be objectively evident to any State conducting itself in the matter in accordance with normal practice and good faith.
In this provision, the meaning of the term "objectively evident " remains to be clarified as well as whether there really is a general practice one can refer to and which is applicable in each and every case. Moreover, the concept of "objective evidence" relies upon the term "good faith" which is a subjective element which therefore is dificult to prove.
Luckily, the value of this provision rests to a large extent with theory. It is almost always in the course of the application and implementation of treaties that the concept of bona fide comes ino play. If a State does not implement a treaty in good faith by violating at least one of its substantial provisions, the Vienna Convention authorizes the other parties to invoke the breach as a ground for terminating the treaty or suspending its operation in whole or in part (Article 60).
A bona fide application or implementation can also have a legitimizing effect in case the treaty is invalidated: According to Article 69 (2)(b), acts performed in good faith before the invalidity was invoked are not rendered unlawful by reason only of the invalidity of the treaty.
As a matter of course, there cannot be a legitimizing effect for a party to which fraud, an act of corruption or coercion is imputable (Article 69(3)). The injured party or parties are then entitled to require any other party to establish as far as possible in their mutual relations the position that would have existed if the acts had not been performed.
A State Party who wishes to impeach the validity of a treaty, to terminate it, to withdraw from it or to suspend its operation must notify the other parties of its claim in order to give them an opportunity to raise an objection against it. For this purpose, the Vienna Convention foresees a time limit of three months after the receipt of the notification (Article 65(2)). After the end of this time limit, the State can declare the invalidity of the treaty through a document signed by one of its representatives.
With the exception of cases of special urgency, this instrument cannot be communicated before the end of the period of three months foreseen in Article 65 (2). If, however, an objection has been raised by at least one other party, the States Parties are under an obligation to seek a solution through the means indicated in article 33 of the Charter of the United Nations.