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Law of Treaties (Vienna Convention, 1969)

The Vienna Convention on the Law of Treaties (VCLT), 1969 codifies the customary rules governing international agreements written between states.

1. Definition and Creation of Treaties

Under Article 2, a treaty is an international agreement concluded between states in written form and governed by international law, whether embodied in a single instrument or two or more related instruments.

Steps to Conclude a Treaty:

  1. Negotiation and Adoption of text.
  2. Signature (Expresses intent, but does not bind the state unless the treaty specifies).
  3. Ratification: The formal domestic executive approval and deposit of instruments of ratification, which establishes the state's consent to be bound.

2. Pacta Sunt Servanda (Article 26)

📜 Art 26 VCLT: Pacta Sunt Servanda
Every treaty in force is binding upon the parties to it and must be performed by them in good faith. Article 27 adds that a party cannot invoke its internal municipal law as a justification for failing to perform a treaty.

3. Doctrine of Reservation (Articles 19-21)

A unilateral statement made by a state when signing or ratifying a treaty, whereby it purports to exclude or modify the legal effect of certain provisions of the treaty in their application to that state.

  • Reservations are allowed unless prohibited by the treaty, or if they are incompatible with the object and purpose of the treaty (*Advisory Opinion on Genocide Convention*).

4. Termination of Treaties

A treaty may be terminated or suspended under these valid grounds:

  • Material Breach (Article 60): A repudiation of the treaty or violation of an essential provision allows other parties to suspend or terminate it.
  • Supervening Impossibility (Article 61): Permanent disappearance or destruction of an object indispensable for the execution of the treaty.
  • Rebus Sic Stantibus (Article 62): A fundamental, unforeseen change of circumstances which constituted an essential basis of consent, making performance radically different from what was originally undertaken.