material breach and supervining impossibility of performance

1. Termination of the operation of
treaties

2. • May result from the external or internal
grounds
• General rule for internal grounds (Art 54):
- in the conformity with the provisions of the
treaty
- at any time by consent of all parties after
consultation with other parties
• External grounds: material breach, supervining
impossibility, fundamental change of
cirmcumstances

3. 1) Material breach
• General rule is that a right to terminate does
not arise unless the breach is a material
(serious) one
• Art 60(3) defines “material breach”
- Repudiation of the treaty not sanctioned by
the present Convention
- The violation of a provision essential to the
accomplishment of the object and purpose of
the treaty

4. • Bilateral treaty – injured party enables to
terminate and suspend the treaty at its
discretion, claiming compensation instead of
or in addition to
• Multilateral treaty – enables all parties by
unanimous decision to terminate the treaty or
to terminate it for the defaulting State only
• Case: Nambia case & The Gabcikovo
Nagymaros case

5. 2) Supervining impossibility of performance
• Well established and uncontested
• Art 61 of Vienna Convention limits this ground
– “permanent disappearance or destruction of
an object indispensable for the execution of
the treaty”
• Cannot be invoked by a party that was itself
instrumental in causing these circumstances

6. Gabcikovo-Nagymaros Project case
• Hungary and Czechoslovakia – treaty in 1977 to
facilitate the construction of dams on the Danuba River
• H suspended works, arguing that to establish a joint
economic investment , the treaty was inconsistent with
environmental consideration
• C carried out unilateral measures in response to H’s
failure to perform the treaty
• Hungary – claimed right to terminate under Art 61
• Held: since H didn’t carry out most of works for which it
was responsible, the impossibility resulted from H’s own
breach of an obligation flowing from treaty. Referring to
Art 61 (2), the termination was invalid

8. Fundamental change of circumstances
(rebus sic stantibus)
• Legal basis for such rule on the basis of the
doctrine - coventio omnis intelligitur rebus sic
stantibus: all treaties are concluded subject to
an implied condition rebus sic stantibus
(things remaining as they are)
• According to modern IL, this rule applies only
in the most exceptional circumstances;
otherwise it could be used as an excuse to
evade all sorts of inconvenient treaty
obligations

9. • Art 62 confines the rule within narrow limits.
FCOC may with certain strict limits, entitles a
party to invoke the change as ground for
terminating, withdrawing
• It may not invoke to a treaty establishing a
“boundary”
• A State may not invoke art 62 if the change was
caused by a breach of its own international
obligations – either treaty in question or
international agreement
• Cases: The Fisheries Jurisdiction case &
Gabcikovo-Nagymaros Project case