Invalidation of Treaty
A treaty concluded by the parties may on various grounds subsequently be invalidated. Arts. 46-53 of the Vienna Convention provide the grounds of invalidity which are as follows (under Arts. 52 and 53, the treaty becomes automatically void)
Lack of proper authority of the representative (Art. 47).
Error in the treaty (Art. 48) - discussed earlier in this chapter.
Fraud committed by another party (Art. 49).
Corruption of the representative (Art. 50).
Coercion of a representative (Art. 51).
Coercion of a State (Art. 52) - A treaty is void if its conclusion has been procured by the threat or use of force in violation of the principles of international law embodied in the U.N. Charter. The above rule implies that economic and political coercion will not invalidate a treaty (as such pressures are part of the normal working of the relations between States). Further, it is difficult to distinguish between the legitimate and illegitimate use of such form of pressure as a means of securing consent to treaties. In the Fisheries Jurisdiction case, the ICJ had also occasion to consider the validity of treaties concluded under coercion. The court observed that a treaty concluded under the threat or use of force is void. The allegation that a given treaty it concluded under coercion is a very serious accusation, and it cannot be based on the grounds of a vague general charge, unfortified by evidence in its support. Such a question should be decided by an international body, preferably the ICJ.
Jus cogens - A treaty shall be void if it conflicts with the general principles of international law.
Non-compliance with domestic law of a State?
Art. 27 of the Vienna Convention provides that a State may not invoke the provisions of its internal law as justification for its failure to perform a treaty. The provision thus strengthens pacta sunt servanda rule. However, the provision is without prejudice to Art. 46 of the Convention which establishes that a State may not invoke the fact that its consent to be bound by a treaty has been expressed in violation of a provision of its internal law regarding competence to conclude treaties as invalidating its consent unless that violation was manifest and concerned a rule of its internal law of fundamental importance. It is further provided that a violation is manifest if it would be objectively evident to any State conducting itself in the matters in accordance with normal practice and in good faith.
Termination of Treaties
When a treaty comes to an end it is regarded as to that of termination of a treaty. While it is true in the case of bilateral treaties, where the defection of one party terminates the treaty, in the case of a multilateral treaty position is different as here the defection or withdrawal of one party does not involve the end of the treaty as between other parties to it. The treaty comes to an end with regard to defected party only. Sec. 3 of the Vienna Convention lays down the different ways by which a treaty comes to an end:-
(i) By consent of the parties - A treaty may be terminated at any time by the consent of all the parties after consultation with the other contracting States [Art. 54(b)].
(ii) By denunciation or withdrawal of a party (Art. 56).
(iii) By concluding another treaty - relating to the same subject matter, and the parties intend that the matter should be governed by the subsequent treaty. Further, a treaty shall be considered as terminated if the provisions of the later treaty are so incompatible with those of the earlier one that the two treaties are not capable of being applied at the same time (Art. 59).
(iv) By material breach - A material breach of a bilateral treaty by one party entitles the other party to terminate treaty (Art. 60). The term ‘material breach’ means a repudiation of the treaty not sanctioned by the Convention or the violation of a provision essential to the accomplishment of the object or purpose of treaty. However, a party may lose its right to invoke the breach if, after becoming aware of the facts, it expressly or impliedly agrees that the treaty remains in force or continues in operation.
(v) Impossibility of performance - Sometimes events or developments occurring outside the treaty subsequent to its conclusion, make the performance of treaty impossible (Art. 61). The permanent destruction or disappearance of a party is a ground for automatic dissolution of a treaty in case succession does not take place. Further, a treaty is terminated where a treaty provides for a joint project on an island which subsequently disappears. However, where the impossibility of performance is only temporary (viz. existence of an emergency in a State might prevent it to comply with its treaty obligations temporarily), the treaty may only be suspended.
(vi) According to provisions of the treaty - A treaty made for a fixed period or specific object, comes to an end after the expiration of that period or fulfilment of the object.
(vii) Outbreak of war - Some treaties are completely terminated, others remain unaffected whereas some others are simply suspended during the war.
(viii) Jus cogens - If a new peremptory norm emerges and the treaty is in conflict with that norm, the treaty terminates.
(ix) Rebus sic stantibus - The occurrence of the fundamental change in the circumstances may terminate a treaty.