Stages of the Conclusion and Entry into Force of Treaties

According to the Convention, the head of the state, the head of the government, and the minister of foreign affairs are authorized to make all acts relating to the conclusion of a treaty by virtue of their functions. For persons other than these, a certificate of authorization, which is called full powers, has to be issued by the competent state authority. The Convention also provides that heads of diplomatic missions are authorized for the act to adopt the text of a treaty between the accrediting state and the state to which they are accredited.

After the adoption of the treaty text, the process of authentication begins. The authentication is made either by the representatives’ signature or initialing of the text of the treaty or, in the case of a treaty adopted in a conference, of the final act of a conference incorporating the text. In the case of treaties concluded within the UN General Assembly, adoption and authentication take place when the General Assembly votes to adopt the resolution incorporating the text of the
treaty. In the case of treaties within the Council of Europe, the adoption of the text is carried out by the vote of the Committee of Ministers, and the authentication is carried out by the signature of either the permanent representative of the member state to the Organization or its diplomat with full powers. 

The means of expressing states’ consent to be bound by a treaty, as set out in the Convention, are signature, exchange of instruments constituting a treaty, ratification, and accession. Apart from these, some other methods can also be used, if the parties so agree.

A treaty can become binding through the signature of a state representative if: (a) the treaty so provides; (b) it is otherwise established that the negotiating states were agreed that signature should have that effect; or (c) the intention of the state to give that effect to the signature appears from the full powers or was expressed during the negotiation.

Another method of expressing consent is the exchange of instruments constituting a treaty. This is acceptable if: (a) the instruments so provide; or (b) it is otherwise established that the states agreed that the exchange of instruments should have that effect.

Ratification, which is also called acceptance or approval in some domestic legal systems, is the name of both the method and the international instrument that indicates the consent of a state to be bound by a treaty. However, before this instrument is issued by the executive branch of the state wishing to be bound by a treaty, the permission to do this should be obtained from the legislature.

If a state which was not present during the treaty negotiations and the authentication stage, may wish to be bound by the treaty at a later stage or even after the treaty enters into force, it can do this through the method of accession. A state can accede to a treaty in this way if: (a) the treaty so provides; (b) it is otherwise established that the negotiating states agreed that such consent may be expressed by means of accession; or (c) all the parties have subsequently agreed that such consent may be expressed by that state by means of accession.

According to the Convention, reservation has been defined as: “a unilateral statement, however phrased or named, made by a state, when signing, ratifying, accepting, approving or acceding to a treaty, whereby it purports to exclude or to modify the legal effect of certain provisions of the treaty in their application to that state”. In practice, a reservation may carry different names such as declaration or understanding. However, whatever the name, if the statement in question is intended to exclude or modify the provisions of the treaty, it constitutes a reservation.

In multilateral treaties, if a reservation is expressly authorized by a treaty, any subsequent acceptance of the reservation by the other contracting states is not required. In cases where there is no such authorization, then, the general rules are as follows: “(a) acceptance by another contracting state of a reservation constitutes the reserving state a party to the treaty in relation to that other state if or when the treaty is in force for those states; (b) an objection by another contracting state to a reservation does not preclude the entry into force of the treaty as between the objecting and reserving states unless a contrary intention is definitely expressed by the objecting state; (c) an act expressing a state’s consent to be bound by the treaty and containing a reservation is effective as soon as at least one other contracting state has accepted the reservation”. Moreover, unless the treaty otherwise provides, “a reservation is considered to have been accepted by a state if it shall have raised no objection to the reservation by the end of a period of twelve months after it was notified of the reservation, or by the date on which it expressed its consent to be bound by the treaty, whichever is later”.

• The Vienna Convention states that a treaty in force is binding on the parties and its provisions must be performed by them in good faith, in line with the principle of pacta sunt servanda.
• In this context, it should also be noted that a state may not invoke a provision of its internal law as a justification for its failure to perform a treaty or to remedy its breach.
• As a rule, treaties do not apply retroactively to acts or facts which took place or any situation which ceased to exist before the date of entry into force of the treaty, unless a different intention appears from the treaty.
• A treaty is applicable upon each party’s entire territory, unless a different intention appears from the treaty. However, it is possible for a treaty to be applicable for a state in certain places subject to the jurisdiction of a state outside the country, in case of activities carried out by state officials abroad, or in certain activities having extraterritorial effects.

According to the general rule in the Vienna Convention, a treaty does not create either obligations or rights for a third state, i.e. a state which is not a party to the treaty in question, without its consent, unless the treaty includes provisions having customary law character. On the other hand, the Convention also provides that an obligation may arise for a third state (or a group of states or all states) from the terms of the treaty if the parties to the treaty so intend and if the third state expressly accepts that obligation in writing. As far as the rights are concerned, it will be again examined if the parties intend to accord rights to the third state and if that state accepts those rights. However, in the case of rights, the consent of the third state will be presumed unless the third state indicates otherwise. When exercising these rights, the third state “shall comply with the conditions for its existence provided for in the treaty or established in conformity with the treaty”. When a right has arisen for a third state, “the right may not be revoked or modified by the parties if it is established that the right was intended not to be revocable or subject to modification without the consent of the third state”. Also, obligations undertaken by the third state in reliance on this right must be compensated. In case of obligations for third states, “the obligation may be revoked or modified only with the consent of the parties to the treaty and of the third state, unless it is established that they had agreed otherwise”.

Article 31 of the Vienna Convention lays down the fundamental rules of interpretation and reflects customary law. Article 31(1) declares that a treaty will be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose. In the second paragraph of the article, the context of a treaty for the purpose of interpretation is defined as comprising: “(a) in addition to the text, including its preamble and annexes; (b) any agreement relating to the treaty which was made between all the parties in connection with the conclusion of the treaty; (c) any instrument which was made by one or more parties in connection
with the conclusion of the treaty and accepted by the other parties as an instrument related to the treaty”. The third paragraph requires that the following shall be taken into account, together with the context: “(a) any subsequent agreement between the parties regarding the interpretation of the treaty or the application of its provisions; (b) any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation; (c) any relevant rules of international law applicable in the relations between the parties”. In the last paragraph of the article, it is provided that a special meaning will be given to a term if it is established that the parties so intended.

In case of successive treaties relating to the same subject matter, Article 30 of the Vienna Convention stipulates that the rights and obligations of the parties will be determined according to the following rules: “(a) when a treaty specifies that it is subject to, or that it is not to be considered as incompatible with, an earlier or later treaty, the provisions of that other treaty prevail; (b) when all the parties to the earlier treaty are parties also to the later treaty[..], the earlier treaty applies only to the extent that its provisions are compatible with those of the later treaty; (c) when the parties to the later treaty do not include all the parties to the earlier one: as between the parties to both treaties, [the earlier treaty applies only to the extent that its provisions are compatible with those of the later treaty]; as between a party to both treaties and a party to only one of the treaties, the treaty to which both states are parties governs their mutual rights and obligations”.

While amendment refers to the alteration of treaty provisions affecting all the parties to that treaty, modification relates to change of certain treaty provisions as between some of the parties.

If the authority of a representative to express the consent of a state to be bound by a particular treaty has been made subject to a specific restriction, the omission to observe that restriction may not be invoked as invalidating the consent, unless the restriction was notified to the other negotiating states prior to his expressing such consent.

Where a state consents to be bound by a treaty as a result of the fraudulent conduct of another negotiating state, it may invoke the fraud as invalidating its consent to be bound. Fraud is intentional representation of a fact different from what it is, thus, fraud is not accepted in legal matters. Where a negotiating state directly or indirectly corrupts the representative of another state in order to obtain the consent, corruption may be invoked as a ground for invalidity, if the connection between the consent and and the provision of benefit can be proven.

A state may not assert the invalidity of its consent to be bound by a treaty, as it has been expressed in violation of a provision of its internal law regarding competence to conclude treaties, unless that violation was manifest and concerned a rule of of fundamental importance. Violation will be regarded as manifest if it would be objectively evident to any state in accordance with normal practice and in good faith. In this respect, in 2002 Cameroon v Nigeria Case, the ICJ noted that a limitation of the capacity of a head of state would not be manifest, unless at least properly publicized. The Court also pointed out that there was no general legal obligation for states to keep themselves informed of legislative and constitutional developments in other states. 

Error occurs when a fact or situation that leads a state to be bound by a treaty is assumed to exist even though it does not. A state may only invoke an error as invalidating its consent if the fact or situation form an essential basis of its consent and have existed at the time when the treaty was concluded. If the circumstances were such as to put that state on notice of a possible error, or if the state contributed to that error by its own conduct, then, it cannot claim error to free itself from the obligation of observing the treaty. An error relating to a legal point does not affect the validity of the treaty. In the 1960 Temple Case, the ICJ rejected Thailand’s argument to invalidate its consent as it was based upon an error in a particular map.

If a treaty is concluded under threats or acts of coercion directed against a state representative, the consent to be bound under such circumstances will be deemed invalid. Such coercion include blackmailing and threats against the representative’s family. Article 52 of the Convention also provides that treaties concluded by threat or use force directed against a state itself, in violation of principles embodied in Article 2(4) of the UN Charter, will be void. The threat or use of force in question here are normally understood as armed ones, therefore, the application of economic and political pressure upon a state to secure its consent may not result in the invalidity of a treaty.

An invalid treaty is void and without legal force. However, if acts have nevertheless been performed in reliance on such a treaty: “(a) each party may require any other party to establish as far as possible in their mutual relations the position that would have existed if the acts had not been performed; (b) acts performed in good faith before the invalidity was invoked are not rendered unlawful by reason only of the invalidity of the treaty [..] except with respect to the party to which the fraud, the act of corruption or the coercion is imputable”. In the case of the invalidity of a particular state’s consent to be bound by a multilateral treaty, the foregoing rules apply only in the relations between that state and the parties to the treaty. Where a treaty is void due to a conflict with a peremptory norm, the parties are required “to eliminate as far as possible the consequences of any act performed in reliance on any provision which conflict with such norm and bring their mutual relations into conformity with the peremptory norm”. 

A material breach is defined as: “(a) repudiation of the treaty not sanctioned by the Convention; or (b) the violation of a provision essential to the accomplishment of the object or purpose of the treaty”.

According to article 61 of the Convention, if an object that is indispensable for the execution of the treaty permanently disappears or destructed (e.g. a treaty for building a dam on a river which dries up), this gives the parties the right to terminate or withdraw from the treaty. If the impossibility is temporary, it may be invoked only as a ground for suspending the treaty. However, this ground cannot be invoked by a party “if the impossibility is the result of a breach by that party either of an obligation under the treaty or of any other international obligation owed to any other party to the treaty”. Termination of a treaty on this ground does not result in the loss of acquired rights by the parties while the treaty was in force.

Article 63 of the Convention recognizes that “the severance of diplomatic or consular relations between the parties to a treaty does not affect the legal relations established between them by the treaty except insofar as the existence of diplomatic or consular relations is indispensable for the application of the treaty”. Article 74 also stipulates that the severance of diplomatic or consular relations between two or more states does not prevent the conclusion of treaties between those states.

In this respect, factors such as the intention of the parties, the nature of the treaty and the extent of the conflict have to be taken into account. A treaty may also contain provisions regulating how it will be applied in the event of a war (e.g. articles 19-21 of the Montreaux Convention) or the treaty may be related to the rules to be applied in war (e.g.the Hague and Geneva Conventions). It is also accepted that treaties of neutrality, human rights, environmental protection, trade, international waterways and international dispute settlement will not be affected by war. Diplomatic or consular treaties may be suspended in the event of war, however, treaties establishing an alliance or nonaggression will be terminated. In this regard, Article 3 of the Draft Articles on the Effects of Armed Conflicts on Treaties adopted by the International Law Commission in 2011 provides that the existence of an armed conflict does not terminate or suspend the treaties as between the states parties to the conflict and as between a state party to the conflict and a state that is not. Article 14 of the Draft further provides that a state exercising its right of self-defence is entitled to suspend in whole or in part the operation of a treaty to which it is a party insofar as that operation is incompatible with the exercise of that right. In this matter, one must also note article 75 of the Convention, which states that its provisions are “without prejudice to any obligation in relation to a treaty which may arise for an aggressor state in consequence of measures taken in conformity with the UN Charter with reference to that state’s aggression”.

The procedure envisaged by the Convention is as follows: the party wishing to invoke either the invalidity of its consent to be bound by a treaty or other grounds for terminating it, withdrawing from it or suspending its operation, must notify in writing the other parties of its claim. The notification should indicate the measures proposed to be taken with respect to the treaty and the reasons therefor. If no objection is raised within at least 3 months, the party making the notification may carry out the proposed measure. If there is an objection, then a dispute has arisen between the parties and it must be resolved by peaceful means indicated in Article 33 of the UN Charter. If a dispute has not been resolved within twelve months by the peaceful means, then any one of the parties may set in motion the conciliation procedure laid down in the Annex to the Convention. If the dispute concerns peremptory norms, any one of the parties may submit it to the International Court of Justice.