## Facts

- The United Nations General Assembly requested an advisory opinion concerning reservations to the 1948 Convention on the Prevention and Punishment of the Crime of Genocide.
- The Convention did not contain a clause expressly authorizing or prohibiting reservations.
- States had begun ratifying or acceding to the Convention with reservations, and other states had objected to some of those reservations.
- The request asked how reservations and objections affect whether a reserving state is a party, and the legal effects of objections by (i) parties, (ii) signatories not yet ratified, and (iii) states not yet signatories or parties.
- The Court addressed the problem in light of the Convention’s special humanitarian character and the shared interest of states in preventing and punishing genocide.

## Issues

1. Whether a state that ratifies or accedes subject to a reservation may be regarded as a party when one or more parties object and others do not.
2. If so, what legal effects follow between the reserving state and (a) objecting parties and (b) accepting parties.
3. What legal effect an objection has when made by (a) a signatory that has not yet ratified or (b) a state entitled to sign or accede but that has not done so.

## Decision

- The Court concluded that reservations are not automatically prohibited merely because a multilateral treaty is silent on reservations.
- The permissibility of a reservation turns on whether it is compatible with the object and purpose of the treaty.
- No single, abstract rule could resolve all reservation scenarios; permissibility and effects depend on the content of the reservation and the treaty’s character.
- A state cannot be bound by a reservation to which it has not consented; accordingly, treaty relations may differ depending on which states accept or object to the reservation.
- A non-signatory cannot, by objecting, exclude another state from the Convention.
- A signatory that has not yet ratified may object, but such an objection has no immediate legal effect and functions as a notice of the stance the state intends to take if it becomes a party.

## Legal Principles

- In the absence of a reservations clause, reservations to a multilateral treaty are assessed under an object-and-purpose compatibility test rather than being presumptively forbidden or presumptively allowed.
- The Genocide Convention’s object and purpose—preventing and punishing genocide—limits permissible reservations; a reservation impairing the treaty’s essential guarantees is incompatible.
- Consent remains controlling in the sense that an objecting state is not bound to accept treaty relations modified by a reservation it rejects.
- Objections do not necessarily exclude the reserving state from the treaty for all states; treaty relations may be relative, with party status and obligations varying across bilateral relationships.
- Only states with a relevant treaty status can produce legal effects through objections: non-signatories cannot exclude a state, and non-ratifying signatories’ objections are prospective rather than immediately operative.

## Conclusion

The advisory opinion established that the validity of reservations to the Genocide Convention depends on compatibility with the treaty’s object and purpose, while recognizing that objections operate through state consent and can produce non-uniform treaty relations; objections by non-signatories cannot exclude a state, and objections by non-ratifying signatories are only declaratory pending ratification.


Reservations to the Convention on the Prevention and Punishment of the Crime of Genocide, Advisory Opinion, 1951 I.C.J. 15 (May 28)