Treaty law

Vienna Convention on the Law of Treaties
Signed 23 May 1969
Location Vienna
Effective 27 January 1980
Condition Ratification by 35 states[1]
Signatories 45
Parties 113 (as of January 2013)[2]
Depositary UN Secretary-General
Languages Chinese, English, French, Russian and Spanish[1]

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[3] and opened for signature on 23 May 1969.[1] The Convention entered into force on 27 January 1980.[1] The VCLT has been ratified by 113 states as of January 2013.[2] 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.[3] During the twenty years of preparation, several draft versions of the convention and commentaries were prepared by special rapporteurs of the ILC.[3] James Brierly, Hersch Lauterpacht, Gerald Fitzmaurice and Humphrey Waldock were the four special rapporteurs.[3] In 1966, the ILC adopted 75 draft articles which formed the basis for the final work.[4] 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.[3][4]

Content and effects

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.[5] It does apply, however, to treaties between states within an intergovernmental organization.[6] However, agreements between states and international organizations, or between international organizations themselves, will be governed by the 1986 Vienna Convention on the Law of Treaties between States and International Organizations or Between International Organizations if it ever enters into force. Also, in treaties between states and international organizations, the terms of the Convention still apply between the state members.[5] The Convention does not apply to agreements not in written form.[5]

State parties to the convention

There are 113 state parties that have ratified the convention,[2] and 15 states have signed but have not ratified the convention. These countries are: Afghanistan, Bolivia, Cambodia, Côte d'Ivoire, El Salvador, Ethiopia, Ghana, Iran, Kenya, Madagascar, Nepal, Pakistan, Trinidad and Tobago, United States, Zambia.[2] In addition, the Republic of China (Taiwan), which is currently only recognized by Template:Numrec, signed the Convention in 1970 prior to the United Nations General Assembly's vote to transfer China's seat to the People's Republic of China (PRC) in 1971. The PRC subsequently acceded to the Convention.[2] 66 UN member states have neither signed nor ratified the Convention.

Vienna formula

International treaties and conventions contain rules about what entities could sign, ratify or accede to them. Some treaties are restricted to states that are members of the UN or parties to the Statute of the International Court of Justice. In rare cases there is an explicit list of the entities that the treaty is restricted to. More commonly the aim of the founding signatories is that the treaty is not restricted to particular states only and so a wording like "this treaty is open for signature to States willing to accept its provisions" is used (the so-called "All States formula"[7]).

When a treaty is open to "States", for the depositary authority[8] it is difficult or impossible to determine which entities are States. If the treaty is restricted to Members of the United Nations or Parties to the Statute of the International Court of Justice, there is no ambiguity. However, a difficulty has occurred as to possible participation in treaties when entities which appeared otherwise to be States could not be admitted to the United Nations, nor become Parties to the Statute of the International Court of Justice owing to the opposition, for political reasons, of a permanent member of the Security Council or haven't applied for ICJ or UN membership. Since that difficulty did not arise as concerns membership in the specialized agencies, where there is no "veto" procedure, a number of those States became members of specialized agencies, and as such were in essence recognized as States by the international community. Accordingly, and in order to allow for as wide a participation as possible, a number of conventions then provided that they were also open for participation to States members of specialized agencies. The type of entry-into-force clause utilized in the Vienna Convention on the Law of Treaties was later called the "Vienna formula" and its wording was utilized by various treaties, conventions and organizations.[9]

Some treaties that utilize it include provisions that in addition to these States any other State invited by a specified authority or organization (commonly the United Nations General Assembly or an institution created by the treaty in question) can also participate, thus making the scope of potential signatories even broader.

The present Convention shall be open for signature by all States Members of the United Nations or of any of the specialized agencies or of the International Atomic Energy Agency or parties to the Statute of the International Court of Justice, and by any other State invited by the General Assembly of the United Nations to become a party to the Convention, as follows: until 30 November 1969, at the Federal Ministry for Foreign Affairs of the Republic of Austria, and subsequently, until 30 April 1970, at United Nations Headquarters, New York.

— Vienna Convention on the Law of Treaties, Article 81, Signature

See also


External links

  • Convention Text
  • Historic Archives of the United Nations Audiovisual Library of International Law
  • Lecture Series of the United Nations Audiovisual Library of International Law