The Law of Treaties

The law of treaties

The Vienna Convention on the Law of Treaties (or 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 112 states as of November 2010. Some countries that have not ratified the Convention recognize 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." Most nations, whether they are party to it or not, recognize it as the preeminent "Treaty of Treaties"; it is widely recognized as the authoritative guide vis-à-vis the formation and effects of treaties.

The scope of the Convention is limited. It applies only to treaties concluded between states, so it does not cover agreements between states and international organizations or between international organizations themselves, though if any of its rules are independently binding on such organizations, they remain so. It does apply, however, to treaties between states within an...