Termination of Treaties: Breach and Rebus Sic Stantibus

A treaty may come to an end, or be suspended for a time, by agreement or on grounds recognised by law. The Vienna Convention treats these grounds narrowly, because the stability of treaties depends on states not walking away when obligations become inconvenient. This note covers each ground in Articles 54 to 64, the procedure and consequences, and the leading case of Gabčíkovo-Nagymaros.

1. Grounds at a Glance

Figure 1: Termination and suspension under the Vienna Convention

2. By Agreement and Withdrawal

• Terms or consent, Articles 54 and 57. A treaty may be terminated or suspended, or a party may withdraw, in accordance with the treaty or at any time by consent of all parties.
• Fall in parties, Article 55. A multilateral treaty does not end merely because the number of parties falls below the number needed for its entry into force.
• No exit clause, Article 56. A treaty with no provision on termination or withdrawal cannot be denounced unless the parties intended to allow it or a right is implied by its nature; at least twelve months' notice is required.
• Human rights treaties. In General Comment No. 26 (1997), the Human Rights Committee stated that the ICCPR, having no withdrawal clause, cannot be denounced, after North Korea attempted to withdraw.
• Later treaty, Article 59. A treaty ends if all parties conclude a later treaty on the same subject intended to replace it, or the two are so incompatible that they cannot apply together.

3. Material Breach

• Article 60(3). A material breach is a repudiation of the treaty not sanctioned by the Convention, or the violation of a provision essential to accomplishing the treaty's object or purpose.
• Bilateral treaty. The other party may invoke the breach as a ground to terminate the treaty or suspend it in whole or in part.
• Multilateral treaty. The other parties may, by unanimous agreement, suspend or terminate it; a party specially affected may suspend it in its relations with the defaulting state; any party may suspend it if the breach radically changes every party's position.
• Humanitarian exception, Article 60(5). These rules do not apply to provisions protecting the human person in treaties of a humanitarian character, especially those prohibiting reprisals.
• Namibia advisory opinion, 1971. South Africa's material breach of its League mandate entitled the General Assembly to terminate it, and its continued presence in Namibia was illegal.

4. Impossibility and Fundamental Change

• Supervening impossibility, Article 61. Permanent disappearance or destruction of an object indispensable for performance, such as the drying up of a river or the submergence of an island, permits termination; temporary impossibility permits only suspension; it cannot be invoked by a party whose own breach caused it.
• Fundamental change, Article 62. Rebus sic stantibus allows termination or withdrawal only where the circumstances were an essential basis of consent and the change radically transforms the obligations still to be performed; it never applies to boundary treaties or to a change caused by the invoking party's breach.
• Fisheries Jurisdiction (UK v Iceland), jurisdiction, 1973. Iceland's reliance on changes in fishing techniques failed; the Court treated Article 62 as codifying customary law and held that the change must increase the burden of obligations to the extent of making performance essentially different from that originally undertaken.

Figure 2: Testing a claim of fundamental change

5. Gabčíkovo-Nagymaros Project (Hungary/Slovakia), 1997

Under a 1977 treaty, Hungary and Czechoslovakia agreed to build a system of locks and dams on the Danube. Citing ecological concerns, Hungary suspended and then abandoned its works in 1989 and notified termination of the treaty in May 1992. Czechoslovakia proceeded with a unilateral alternative, Variant C, and put it into operation in October 1992. Slovakia succeeded Czechoslovakia in 1993.

Figure 3: Hungary's grounds and the Court's answers

• Outcome. Hungary was not entitled to suspend or abandon its works; Czechoslovakia was entitled to begin preparing Variant C but not to put it into operation; the 1977 treaty remained in force, and both parties were to negotiate in good faith to achieve its objectives, taking account of new environmental norms and the concept of sustainable development.

6. Other Events

• Severance of diplomatic relations, Article 63. Does not affect legal relations under a treaty, except where diplomatic relations are indispensable to its application.
• New jus cogens, Article 64. A conflicting existing treaty becomes void and terminates.
• Armed conflict. Under the ILC Draft Articles on the Effects of Armed Conflicts on Treaties (2011), armed conflict does not by itself terminate or suspend treaties.
• Consequences, Articles 70 and 72. Termination releases the parties from further performance but does not affect rights or obligations created before; suspension releases them for the period of suspension, and they must not act to obstruct resumption.
• Procedure. The notification and dispute procedure of Articles 65 to 68 applies, as for invalidity (Topic 16)
• Indus Waters Treaty. By a letter dated 25 April 2025, India informed Pakistan that the treaty would be held in abeyance, citing sustained cross-border terrorism, Pakistan's refusal to negotiate modifications, and changed circumstances such as population, clean energy needs and water sharing; the treaty itself has no clause for unilateral suspension, and Pakistan disputes India's position.

7. Frequently Asked Questions

Can rebus sic stantibus be used to end a boundary treaty?

No. Article 62(2)(a) excludes treaties establishing a boundary, so that frontiers remain stable whatever changes occur later.

Can a state end a treaty because of a state of necessity?

No. In Gabčíkovo-Nagymaros (1997), the ICJ held that necessity may at most preclude the wrongfulness of non-performance while it lasts; it is not a ground for terminating a treaty, which revives once the necessity ends.

8. Related Topics

• Topic 16: Law of Treaties IV. Invalidity of treaties.
• Topic 26: International Rivers. The Indus Waters Treaty and its status.
• Topic 43: State Responsibility. Necessity and countermeasures.