The Vienna Convention on the Law of Treaties (VCLT) is an

international agreement A treaty is a formal, legally binding written agreement between actors in international law. It is usually made by and between sovereign states, but can include international organizations, individuals, business entities, and other legal perso ...

regulating treaties between states. Known as the "treaty on treaties", it establishes comprehensive rules, procedures, and guidelines for how treaties are defined, drafted, amended, interpreted, and generally operated. An international treaty is a written agreement between international law subjects reflecting their consent to the creation, alteration, or termination of their rights and obligations. The VCLT is considered a codification of

customary international law Customary international law is an aspect of international law involving the principle of custom. Along with general principles of law and treaties, custom is considered by the International Court of Justice, jurists, the United Nations, and its ...

and state practice concerning treaties. The convention was adopted and opened to signature on 23 May 1969,untreaty.un.org
''Law of treaties''
, International Law Commission, last update: 30 June 2005. Consulted on 7 December 2008.Vienna Convention on the Law of Treaties
pg. 1 and it entered into force on 27 January 1980. It has been ratified by 116 states as of January 2018. Some non-ratifying parties, such as the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, recognize parts of it as a restatement of customary international law and binding upon them as such. The VCLT is regarded as one of the most important instruments in treaty law and remains an authoritative guide in disputes over treaty interpretation.

History

The VCLT was drafted by the

International Law Commission The International Law Commission (ILC) is a body of experts responsible for helping develop and codify international law. It is composed of 34 individuals recognized for their expertise and qualifications in international law, who are elected by t ...

(ILC) of the United Nations, which began work on the convention in 1949. During the 20 years of preparation, several draft versions of the convention and commentaries were prepared by special rapporteurs of the ILC, which included prominent international law scholars James Brierly,

Hersch Lauterpacht Sir Hersch Lauterpacht (16 August 1897 – 8 May 1960) was a British international lawyer, human rights activist, and judge at the International Court of Justice. Biography Hersh Lauterpacht was born on 16 August 1897 to a Jewish family in t ...

, Gerald Fitzmaurice, and

Humphrey Waldock Sir Claud Humphrey Meredith Waldock, (13 August 1904 – 15 August 1981) was a British jurist and international lawyer. Education Waldock was born to a tea planter and his wife in Colombo, Ceylon. He attended Uppingham School and went up to ...

. In 1966, the ILC adopted 75 draft articles, which formed the basis for its 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 on the following day.

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" and affirms that "every state possesses the capacity to conclude treaties." 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. Article 26 defines ''

pacta sunt servanda ''Pacta sunt servanda'', Latin for "agreements must be kept", is a brocard and a fundamental principle of law. According to Hans Wehberg, a professor of international law, "few rules for the ordering of Society have such a deep moral and religi ...

'', Article 53 proclaims

peremptory norm A peremptory norm (also called or ' ; Latin for "compelling law") is a fundamental principle of international law that is accepted by the international community of states as a norm from which no derogation is permitted. There is no universal ...

, and Article 62 proclaims Fundamental Change of Circumstance. The convention has been referred to as the "treaty on treaties" and 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

recognizes that parts of the Convention constitute customary law binding on all states. The

Supreme Court of India The Supreme Court of India ( IAST: ) is the supreme judicial authority of India and is the highest court of the Republic of India under the constitution. It is the most senior constitutional court, has the final decision in all legal matters ...

has also recognised the customary status of the convention.

Scope

The Convention applies only to treaties that came after it was made and to those concluded between states and so does not govern agreements between states and

international organization An international organization or international organisation (see spelling differences), also known as an intergovernmental organization or an international institution, is a stable set of norms and rules meant to govern the behavior of states a ...

s or between international organizations themselves, but if any of its rules are independently binding on such organizations, they remain so.Article 3
of the Convention. The VCLT applies to treaties between states within an intergovernmental organization. However, agreements between states and international organizations or between international organizations themselves are governed by the 1986

Vienna Convention on the Law of Treaties between States and International Organizations or Between International Organizations #REDIRECT Vienna Convention on the Law of Treaties Between States and International Organizations or Between International Organizations ...

if it enters into force. Furthermore, in treaties between states and international organizations, the terms of the Convention still apply between the state members. The Convention does not apply to unwritten agreements.

Parties to the convention

As of January 2018, there are 116 state parties that have ratified the convention, and a further 15 states have signed but have not ratified the convention. In addition, the

Republic of China Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the northeas ...

(Taiwan), which is currently recognized by only , signed the Convention in 1970 prior to the

UN General Assembly The United Nations General Assembly (UNGA or GA; french: link=no, Assemblée générale, AG) is one of the six principal organs of the United Nations (UN), serving as the main deliberative, policymaking, and representative organ of the UN. Curr ...

's 1971 vote to transfer China's seat to the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

, which subsequently acceded to the convention. There are 66

UN member states The United Nations member states are the sovereign states that are members of the United Nations (UN) and have equal representation in the UN General Assembly. The UN is the world's largest intergovernmental organization. The criter ...

that have neither signed nor ratified the convention.

Vienna formula

Signature, ratification and accession

International treaties A treaty is a formal, legally binding written agreement between actors in international law. It is usually made by and between sovereign states, but can include international organizations, individuals, business entities, and other legal pe ...

and conventions contain rules about what entities could

sign A sign is an object, quality, event, or entity whose presence or occurrence indicates the probable presence or occurrence of something else. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm, or ...

ratify Ratification is a principal's approval of an act of its agent that lacked the authority to bind the principal legally. Ratification defines the international act in which a state indicates its consent to be bound to a treaty if the parties inten ...

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 negotiating states (most or all of which usually end up becoming the founding signatories) is that the treaty is not restricted to particular states and so a wording like "this treaty is open for signature to ''States'' willing to accept its provisions" is used (the "all states formula"All States are defined as all UN member states and states about which there are individual statements of inclusion by the UN Secretary-General or other UN organ
Repertory of Practice of United Nations Organs Supplement No. 8; page 10UN THE WORLD TODAY (PDF)
the

United Nations Secretary-General The secretary-general of the United Nations (UNSG or SG) is the chief administrative officer of the United Nations and head of the United Nations Secretariat, one of the six principal organs of the United Nations. The role of the secretary- ...

has stated that when the "any State" or "all States" formula is adopted, he would be able to implement it only if the General Assembly provided him with the complete list of the States coming within the formula, other than those falling within the "Vienna formul
UN Office of Legal Affairs
/ref>). In the case of regional organisations, such as the

Council of Europe The Council of Europe (CoE; french: Conseil de l'Europe, ) is an international organisation founded in the wake of World War II to uphold human rights, democracy and the rule of law in Europe. Founded in 1949, it has 46 member states, with a p ...

or the

Organization of American States The Organization of American States (OAS; es, Organización de los Estados Americanos, pt, Organização dos Estados Americanos, french: Organisation des États américains; ''OEA'') is an international organization that was founded on 30 Apri ...

, the set of negotiating states that once agreed upon may sign and ratify the treaty is usually limited to its own member states, and non-member states may accede to it later. However, sometimes a specific set of non-member states or non-state actors may be invited to join negotiations. For example, the Council of Europe invited the "non-member States"

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

, the

Holy See The Holy See ( lat, Sancta Sedes, ; it, Santa Sede ), also called the See of Rome, Petrine See or Apostolic See, is the jurisdiction of the Pope in his role as the bishop of Rome. It includes the apostolic episcopal see of the Diocese of R ...

(

Vatican City Vatican City (), officially the Vatican City State ( it, Stato della Città del Vaticano; la, Status Civitatis Vaticanae),—' * german: Vatikanstadt, cf. '—' (in Austria: ') * pl, Miasto Watykańskie, cf. '—' * pt, Cidade do Vati ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

Mexico Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...

and the

to "participate in the elaboration" of the 2011 Istanbul Convention and specifically allowed the

European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are located primarily in Europe, Europe. The union has a total area of ...

(described as an "International Organisation," rather than a "State") to sign and ratify the convention, rather than accede to it, and "other non-member States" were allowed only accession. The act of signing and ratifying a treaty as a negotiating state has the same effect as the act of acceding to a treaty (or "acceding a treaty") by a state that was not involved in its negotiation. Usually, accessions occur only after the treaty has entered into force, but the UN Secretary General has occasionally accepted accessions even before a treaty went into force. The only downside of not being a negotiating state is that one has no influence over the contents of a treaty, but one is still allowed to declare reservations with respect to specific provisions of the treaty that one wishes to accede to (Article 19).

Statehood question

When a treaty is open to "States", it may be difficult or impossible for the depositary authority 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 that appeared otherwise to be States could not be admitted to the United Nations or become Parties to the Statute of the International Court of Justice because of the opposition for political reasons of a permanent member of the Security Council or have not applied for ICJ or UN membership. Since that difficulty did not arise as concerns membership in the specialized agencies, on which there is no "veto" procedure, a number of those States became members of specialized agencies and so were in essence recognized as States by the

international community The international community is an imprecise phrase used in geopolitics and international relations to refer to a broad group of people and governments of the world. As a rhetorical term Aside from its use as a general descriptor, the term is t ...

. Accordingly, 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 used in the Vienna Convention on the Law of Treaties was later called the "Vienna formula," and its wording was used by various treaties, conventions and

organizations An organization or organisation (Commonwealth English; see spelling differences), is an entity—such as a company, an institution, or an association—comprising one or more people and having a particular purpose. The word is derived from ...

. Some treaties that use 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 The United Nations General Assembly (UNGA or GA; french: link=no, Assemblée générale, AG) is one of the six principal organs of the United Nations (UN), serving as the main deliberative, policymaking, and representative organ of the UN. Curr ...

or an institution created by the treaty in question) can also participate, thus making the scope of potential signatories even broader.

Interpretation of treaties

Articles 31-33 of the VCLT entail principles for interpreting conventions, treaties etc. These principles are recognized as representing customary international law, for example by the

(ILC). The interpretational principles codified in Article 31 are to be used before applying those of Article 32, which explicitly states that it offers supplementary means of interpretation. The

European Court of Justice The European Court of Justice (ECJ, french: Cour de Justice européenne), formally just the Court of Justice, is the supreme court of the European Union in matters of European Union law. As a part of the Court of Justice of the European U ...

has also applied the interpretational provisions of the VCLT in different cases, including the ''Bosphorus Queen Case'' (2018), in which the court interpreted the extent of the term "any resources" in Article 220(6) of UNCLOS. The VCLT is often relied upon in investment arbitration cases.

Footnotes

External links

Convention Text

b
Karl Zemanek
procedural history note and audiovisual material on the ''Vienna Convention on the Law of Treaties'' in th

* ttp://legal.un.org/avl/ls/Rosenboom_LT.html Lecturesb
Annebeth Rosenboom
entitled ''Practical Aspects of Treaty Law: The Depositary Functions of the Secretary-General'' and ''Practical Aspects of Treaty Law: Treaty Registration under Article 102 of the Charter of the United Nations'' (both lectures also available in French) in th

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