The contribution’s objective is to analyse the interim obligation of a State not to defeat the object and purpose of a treaty between its signature and entry into force on the basis of the text of Article 18 of the Vienna Convention on the Law of Treaties (VCLT), doctrine and judicial decisions.
The contribution’s objective is to analyse the interim obligation of a State not to defeat the object and purpose of a treaty between its signature and entry into force on the basis of the text of Article 18 of the Vienna Convention on the Law of Treaties (VCLT), doctrine and judicial decisions. The contribution concludes that it is a legal obligation of customary international law, codified in the mentioned Article of the VCLT. A State violates it if it defeats the object
of purpose of a treaty – understood as a single term – by defeating with its acts
an essential element of the treaty that is necessary to its general tenor, in such
a way that it impairs the raison d’être of the treaty. A violation of Article 18
must prima facie be objective, irrespective of the State’s subjective relation to
the violation. However, this does not reflect the understanding of that Article
on the basis of travaux préparatoires of the VCLT and the doctrine, according
to which a certain subjective element needs to be demonstrated when assessing the State’s conduct, although there is currently no consensus as to what
test might be the most appropriate for that assessment. Article 18 of the VCLT
leaves open also some other seemingly less important issues that are nevertheless essential for its effectiveness. These issues have not been discussed by the
doctrine or have been only marginally, and so the author attempted to resolve
them or at least provide some guidance in that respect. The author thus – inter
alia by comparison with the similar provision of Article 25 of the VCLT on
provisional application – explains that the declaration of the intent of a State
provided in point (a) of the said Article not to become party to the treaty is
effective ex nunc, and that it can be withdrawn in certain circumstances.