termination of treaty

Termination of a treaty ends its legal force for the parties concerned, releasing them from any further obligation to perform. It is distinct from suspension (which only pauses operation) and from withdrawal (which removes a single party while the treaty continues among the rest), although the Vienna Convention on the Law of Treaties (VCLT) of 1969 groups these together in Part V, Section 3.

Under the VCLT, termination may occur on several grounds:

• By the treaty's own terms (Art. 54(a)) — for example, an expiry date or a denunciation clause.
• By consent of all parties (Art. 54(b)), after consultation with the other contracting states.
• Implied right of denunciation (Art. 56) where the treaty is silent, only if the parties intended to admit such a right or it can be inferred from the nature of the treaty; 12 months' notice is required.
• Material breach (Art. 60), allowing the injured party or, in multilateral treaties, the other parties acting unanimously, to invoke termination.
• Supervening impossibility of performance (Art. 61), e.g. the permanent disappearance of an object indispensable to execution.
• Fundamental change of circumstances — rebus sic stantibus (Art. 62), narrowly construed by the ICJ in Gabčíkovo-Nagymaros (Hungary/Slovakia, 1997).
• Emergence of a new peremptory norm of general international law (Art. 64).

Procedure is governed by Articles 65–67: a party must notify the others in writing, stating the measure proposed and reasons. If no objection arises within three months, termination may proceed; if objected to, the parties must seek a solution through the means listed in Article 33 of the UN Charter.

Termination does not affect rights, obligations, or legal situations already created through execution prior to termination (Art. 70). Boundary treaties and certain humanitarian obligations are generally regarded as immune to unilateral termination.