Article 45 Vienna Convention on the Law of Treaties
Loss of a right to invoke a ground for invalidating, terminating, withdrawing from or suspending the operation of a treaty
A State may no longer invoke a ground for invalidating, terminating, withdrawing from or suspending the operation of a treaty under articles 46 to 50 or articles 60 and 62 if, after becoming aware of the facts:
(a) it shall have expressly agreed that the treaty is valid or remains in force or continues in operation,
as the case may be; or
(b) it must by reason of its conduct be considered as having acquiesced in the validity of the treaty or in its maintenance in force or in operation, as the case may be.
See also: Article 44 Vienna Convention on the Law of Treaties
