The Law of Treaties

What is a treaty? A treaty is an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation (1969 Vienna Convention on the Law of Treaties, Article 2).

The Types of Treaties Classification by level: Inter-State treaties Intergovernmental treaties Inter-ministerial (inter-agency) treaties Classification by number of parties: Bilateral Multilateral

Modes of expressing consent Consent by signature Consent by ratification Consent by acceptance / approval Consent by exchange of instruments Consent by accession

Reservations to treaties A reservation is 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 (Vienna Convention 1969, Article 2). NB: reservations vs. understandings, political statements or interpretive declarations. NB: object and purpose of the treaty in question!!!

The entry into force of treaties Entry into force – in accordance with treaty provisions Registration in the UN Secretariat and publication

The application of treaties Pacta sunt servanda Application of successive treaties Third States

The amendment and modification of treaties Amendment – procedure applicable all parties to a treaty Modification – procedure applicable to a number of parties to a treaty

The interpretation of treaties Textual (literal) interpretation Circumstantial interpretation (traveaux preparatoires) Teleological (purpose-related) interpretation

The invalidity of treaties Municipal law Error Fraud and corruption Coercion Jus cogens

The termination of treaties Termination by treaty provision or consent Material breach Supervening impossibility of performance Fundamental change of circumstances (rebus sic stantibus)