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.
