Requirements
Art 2(1)(a): “‘Treaty’ means an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation”.
Additional requirements
Intention to create legal relations
ILC: This is implicit in the phrase “governed by international law” in Art 2(1)(a), VCLT. requirement explains why Memoranda of Understanding and other written soft law instruments are not treaties
Greece v Turkey (Aegean Sea Continental Shelf): A “joint communique” issued by the Greek and Turkish PMs was not a treaty because an intention to create legal relations could not be found.
Specificity
Iran v USA (Oil Platforms): Although a treaty is legally binding, a particular provision in it may be “drafted in terms so general that by itself it is not capable of generating legal rights and obligations”. Thus, Art 1 of the Treaty of Friendship 1955, which provided that “there shall be firm and ensuring peace and sincere friendship between the United States and… Iran”, did not generate legal rights and obligations (although it could be used to interpret the rest of the treaty).
No need for registration
Art 80, VCLT; Art 102(1), UN Charter: Treaties should be registered, but registration does not make a treaty valid nor does non-registration make a treaty non-valid.
Qatar v Bahrain: “Non-registration or late registration… does not have any consequences for the validity of the actual validity of the treaty, which remains no less binding upon the parties.”
Substantive, not formal, determination
Qatar v Bahrain: “[I]nternational agreements may take a number of forms and be given a diversity of names”.
Greece v Turkey (Aegean Sea Continental Shelf): Whether an agreement constitutes a treaty
“essentially depends on the nature of the act or transaction to which [it] gives expression; and it does not settle the question simply to refer to the form… in which that act or transaction is embodied”. Rather, the court “must have regard to all of its actual terms and the particular circumstances in which it was drawn up”.
Qatar v Bahrain: An exchange of letters can constitute a binding treaty. Meeting minutes which are “not a simple record” of the meeting, but “enumerate the commitments to which the Parties have consented”, can “create rights and obligations in international law for the Parties” and thus constitute a treaty. In these circumstances, a purported intention not to conclude a treaty cannot “prevail over the actual terms of the instrument in question”. By contrast, meeting minutes which are just “diplomatic documents recording the state of progress of the negotiations… [possess] no legally binding force”.
Greece v Turkey (Aegean Sea Continental Shelf): A joint communique can constitute a treaty.
States
Arts 2(1)(a), 3: The VCLT applies only to treaties between states, not to international agreements concluded between states and other subjects of international law or between such other subjects of international law.
Parties
Kasikili/Sedudu Island Case: The VCLT applies only to its parties.
Prospective effect
Art 4: The VCLT only applies to treaties concluded after its entry into force in 1980.
Written treaties
Arts 2(1)(a), 3: The VCLT applies only to treaties “in written form… governed by international law”, not to other types of treaties such as oral agreements.
Customary international law
Arts 3, 4: The non-applicability of the VCLT in certain circumstances does not preclude the applicability of rules of customary international law.
Default nature
The VCLT can be displaced by express provision, so always examine the terms of the treaty first.
1. Authority to conclude treaties
Art 7: A person is considered as representing a state if: (1) he produces full powers, (2) he is considered as representing his State without having to produce full powers in virtue of his functions (e.g. Head of State, Head of Government, Minister for Foreign Affairs) or (3) he is considered as representing his State without having to produce full powers because the State intention was to consider him as representing the State and to dispense with full powers.
Art 8: Consent is ineffective if made by an unauthorised person unless later confirmed by that State.
2. Consent
Art 9: The consent of all the participating States is necessary.
Art 11: Consent may be expressed by signature, exchange of instruments constituting a treaty, ratification, acceptance, approval of accession, or by any other means if so agreed.
Art 12-17: Specific provisions on each mode.
3. Entry into force
Art 24: A treaty enters into force on the date it provides or the negotiating States agree; otherwise, a treaty enters into force as soon as consent to be bound is established for all the negotiating States.
Interim obligation
Art 18: A state is legally obliged to refrain from acts which would defeat the object and purpose of the treaty in the period between signature and ratification (if required) until it has indicated that it will not be a party to the treaty, and also in the period between consent to be bound and entry into force of the treaty, provided the latter is not unduly delayed.
Art 42(1): The grounds for invalidity set out in Arts 46-53 are exhaustive.
Art 69: An invalid treaty has no legal force.
1. Consent expressed in violation of a provision of internal law
Art 46: (1) Consent to be bound expressed in violation of a provision of its internal law; (2) violation manifest, i.e. would have been objectively evident to any State conducting itself in the matter in accordance with normal practice and in good faith; (3) violation concerned a rule of its internal law of fundamental importance.
Eastern Greenland, Spanish Zones of Morocco Claims, Qatar v Bahrain, Cameroon v Nigeria: Arguments of invalidity were given short shrift.
Cameroon v Nigeria: (1) A violation “is not manifest in the sense of Article 46, paragraph 2, unless at least properly publicised” – especially in respect of the group of persons who, under Art 7(2), are considered as representing their State without the need to produce full powers. (2) “[T]here is no general legal obligation for states to keep themselves informed of legislative and constitutional developments in other states which are or may become important for the international relations of these States”.
2. Authority of representative to express consent subject to specific restriction
Art 47: (1) Omission of representative to observe specific restriction on authority to express consent; (2) restriction notified to the other negotiating States prior to his expressing such consent.
3. Error
Art 48: (1) Error relating to fact or situation assumed by State to exist at the time when treaty concluded, (2) fact or situation formed essential basis of its consent, (3) State did not contribute by its own conduct to the error, (4) circumstances were not such as to put State on notice of possible error.
Temple of Preah Vihear: A treaty stated that the boundary between Cambodia and Thailand was to follow the watershed line. On this basis, a map which placed the Temple of Preah Vihear was prepared. Thailand received and accepted the map. Later, however, it argued that the map embodied a material error because it did not follow the watershed line as required by the treaty. The ICJ rejected this argument because “the plea of error cannot be allowed as an element vitiating consent if the party advancing it contributed by its own conduct to the error, or could have avoided it, or if the circumstances were such as to put that party on notice of a possible error. The Court considers that the character and qualifications of the persons who saw the Annex I map on the Siamese side would alone make it very difficult for Thailand to plead error in law.”
4. Fraud
Art 49: Induced to conclude treaty by fraudulent conduct of another negotiating state.
5. Corruption of State representative
Art 50: Expression of consent procured through corruption of representative directly or indirectly by another negotiating State.
Loss of right to invalidate
Art 45: (1) Expressly agrees that treaty is valid or remains in force or continues in operation, or (2) by conduct acquiesces in validity or maintenance in force or in operation.
Nicaragua v Colombia: Nicaragua advanced “the nullity and lack of validity” of a 1925 treaty for the first time in 1980. First, it argued that the treaty had been “concluded in manifest violation of the Nicaraguan Constitution”. Second, it argued that Nicaragua had been under military occupation by the US and was precluded from rejecting the conclusion of treaties that the US demanded it to conclude. However, “for more than 50 years, Nicaragua has treated the 1928 Treaty as valid and never contended that it was not bound by the Treaty”, and “[a]t no time in that 50 years... did Nicaragua contend that the Treaty was invalid for whatever reason”. On the contrary, “Nicaragua has, in significant ways, acted as if the 1928 Treaty was valid”, by not invoking its invalidity in interactions with Columbia in 1969 and the US in 1971. Consequently, Nicaragua “cannot today be heard to assert that the 1928 Treaty was not in force in 1948”. The right of election for a non-breaching party is subject to a time bar of reasonable time after the treaty’s conclusion.
1. Coercion of State representative
Art...