Ratification of Multilateral Treaties

A multilateral treaty becomes legally binding on a state when that state has agreed to be bound and the treaty has entered into force for it. Consent to be bound and entry into force are distinct steps: ratification often supplies consent, but does not necessarily make the treaty immediately operative.

Establishing the state's consent

The Vienna Convention on the Law of Treaties, 1969 provides the standard framework for understanding treaty formation. The treaty's provisions determine which methods states may use to express consent.

• Under Article 11, consent may be expressed through signature, ratification, acceptance, approval, accession or another agreed means.
• Signature establishes consent where the treaty or the states' agreement gives it that effect; where ratification is required, signature alone does not establish full consent.
• Under Article 18, a state that signs subject to ratification must refrain from acts defeating the treaty's object and purpose until it makes clear its intention not to become a party.

Ratification and deposit of instruments

Ratification is the international act through which a state establishes its consent to be bound. It is distinct from domestic procedures, such as parliamentary approval, which may authorise that act.

• For many multilateral treaties, consent is established by depositing an instrument of ratification with the designated depositary, as required by the treaty.
• Acceptance and approval can similarly establish consent; accession enables a state to become bound without first signing, where the treaty permits it.
• The depositary receives and keeps treaty instruments and communicates relevant notifications to states; it does not itself grant consent on their behalf.

Entry into force for the state

Under Article 24, a treaty enters into force according to its provisions or as the negotiating states agree. Multilateral treaties commonly require a specified number of consents and may prescribe a waiting period.

• A state ratifying before that threshold is reached generally awaits the treaty's entry into force.
• For a state joining later, the treaty's provisions determine when its obligations begin.
• Provisional application may operate before entry into force if the treaty provides for it or the negotiating states otherwise agree.

Legal consequences

Under Article 26, every treaty in force binds its parties and must be performed in good faith: this is pacta sunt servanda.

• A party generally cannot invoke its internal law to justify failure to perform the treaty.
• Permissible reservations may modify particular obligations; they cannot be prohibited by the treaty or incompatible with its object and purpose.