Treaty law

Vienna Convention on the Law of Treaties

Vienna Convention on the Law of Treaties   Parties   Signatories   Non-parties
Signed	23 May 1969
Location	Vienna
Effective	27 January 1980
Condition	Ratification by 35 states
Signatories	45
Parties	114 (as of April 2014)
Depositary	UN Secretary-General
Languages	Arabic, Chinese, English, French, Russian and Spanish
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The Vienna Convention on the Law of Treaties (VCLT) is a treaty concerning the international law on treaties between states. It was adopted on 22 May 1969 and opened for signature on 23 May 1969. The Convention entered into force on 27 January 1980. The VCLT has been ratified by 114 states as of April 2014. Some countries that have not ratified the Convention, such as the United States, recognize parts of it as a restatement of customary law and binding upon them as such.

The VCLT was drafted by the International Law Commission (ILC) of the United Nations, which began work on the Convention in 1949. During the twenty years of preparation, several draft versions of the convention and commentaries were prepared by special rapporteurs of the ILC.James Brierly, Hersch Lauterpacht, Gerald Fitzmaurice and Humphrey Waldock were the four special rapporteurs. In 1966, the ILC adopted 75 draft articles which formed the basis for the final work. Over two sessions in 1968 and 1969, the Vienna Conference completed the Convention, which was adopted on 22 May 1969 and opened for signature the following day.

The Convention codifies several bedrocks of contemporary international law. It defines a treaty as "an international agreement concluded between states in written form and governed by international law," as well as affirming that "every state possesses the capacity to conclude treaties." The most important point in the Convention is that Article 1 restricts the application of the Convention to written treaties between States, excluding treaties concluded between the states and international organizations or international organizations themselves.

The Convention has been referred to as the "treaty on treaties"; it is widely recognized as the authoritative guide regarding the formation and effects of treaties. Even those countries who have not ratified it recognize its significance. For example, the United States recognizes that parts of the Convention constitute customary law binding on all nations. In India, the Supreme court has also recognised the customary status of the convention.