Page:Vienna Convention on the Law of Treaties (1969).djvu/8



2. The consent of a State to be bound by a treaty which permits a choice between differing provisions is effective only if it is made clear to which of the provisions the consent relates.

Article 18. Obligation not to defeat the object and purpose of a treaty prior to its entry into force
A State is obliged to refrain from acts which would defeat the object and purpose of a treaty when:
 * (a) it has signed the treaty or has exchanged instruments constituting the treaty subject to ratification, acceptance or approval, until it shall have made its intention clear not to become a party to the treaty; or
 * (b) it has expressed its consent to be bound by the treaty, pending the entry into force of the treaty and provided that such entry into force is not unduly delayed.

Article 19. Formulation of reservations
A State may, when signing, ratifying, accepting, approving or acceding to a treaty, formulate a reservation unless:
 * (a) the reservation is prohibited by the treaty;
 * (b) the treaty provides that only specified reservations, which do not include the reservation in question, may be made; or
 * (c) in cases not falling under sub-paragraphs (a) and (b), the reservation is incompatible with the object and purpose of the treaty.

Article 20. Acceptance of and objection to reservations
1. A reservation expressly authorized by a treaty does not require any subsequent acceptance by the other contracting States unless the treaty so provides.

2. When it appears from the limited number of the negotiating States and the object and purpose of a treaty that the application of the treaty in its entirety between all the parties is an essential condition of the consent of each one to be bound by the treaty, a reservation requires acceptance by all the parties.

3. When a treaty is a constituent instrument of an international organization and unless it otherwise provides, a reservation requires the acceptance of the competent organ of that organization.

4. In cases not falling under the preceding paragraphs and unless the treaty otherwise provides:
 * (a)