This introductory note seeks to provide a basic - but not an exhaustive - overview of the key terms employed in the United Nations Treaty Collection to refer to international instruments binding at international law: treaties, agreements, conventions, charters, protocols, declarations, memoranda of understanding, modus vivendi and exchange of notes. The purpose is to facilitate a general understanding of their scope and function.
Over the past centuries, state practice has developed a variety of terms to refer to international instruments by which states establish rights and obligations among themselves. The terms most commonly used are the subject of this overview. However, a fair number of additional terms have been employed, such as "statutes", "covenants", "accords" and others. In spite of this diversity of terminology, no precise nomenclature exists. In fact, the meaning of the terms used is variable, changing from State to State, from region to region and instrument to instrument. Some of the terms can easily be interchanged: an instrument that is designated "agreement" might also be called "treaty".
The title assigned to such international instruments thus has normally no overriding legal effects. The title may follow habitual uses or may relate to the particular character or importance sought to be attributed to the instrument by its parties. The degree of formality chosen will depend upon the gravity of the problems dealt with and upon the political implications and intent of the parties.
Although these instruments differ from each other by title, they all have common features and international law has applied basically the same rules to all of these instruments. These rules are the result of long practice among the States, which have accepted them as binding norms in their mutual relations. Therefore, they are regarded as international customary law. Since there was a general desire to codify these customary rules, two international conventions were negotiated. The 1969 Vienna Convention on the Law of Treaties ("1969 Vienna Convention"), which entered into force on 27 January 1980, contains rules for treaties concluded between States. The 1986 Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations ("1986 Vienna Convention"), which has still not entered into force, added rules for treaties with international organizations as parties. Both the 1969 Vienna Convention and the 1986 Vienna Convention do not distinguish between the different designations of these instruments. Instead, their rules apply to all of those instruments as long as they meet certain common requirements.
Article 102 of the Charter of the United Nations provides that "every treaty and every international agreement entered into by any Member State of the United Nations after the present Charter comes into force shall as soon as possible be registered with the Secretariat and published by it". All treaties and international agreements registered or filed and recorded with the Secretariat since 1946 are published in the UNTS. By the terms "treaty" and "international agreement", referred to in Article 102 of the Charter, the broadest range of instruments is covered. Although the General Assembly of the UN has never laid down a precise definition for both terms and never clarified their mutual relationship, Art.1 of the General Assembly Regulations to Give Effect to Article 102 of the Charter of the United Nations provides that the obligation to register applies to every treaty or international agreement "whatever its form and descriptive name". In the practice of the Secretariat under Article 102 of the UN Charter, the expressions "treaty" and "international agreement" embrace a wide variety of instruments, including unilateral commitments, such as declarations by new Member States of the UN accepting the obligations of the UN Charter, declarations of acceptance of the compulsory jurisdiction of the International Court of Justice under Art.36 (2) of its Statute and certain unilateral declarations that create binding obligations between the declaring nation and other nations. The particular designation of an international instrument is thus not decisive for the obligation incumbent on the Member States to register it.
It must however not be concluded that the labelling of treaties is haphazard or capricious. The very name may be suggestive of the objective aimed at, or of the accepted limitations of action of the parties to the arrangement. Although the actual intent of the parties can often be derived from the clauses of the treaty itself or from its preamble, the designated term might give a general indication of such intent. A particular treaty term might indicate that the desired objective of the treaty is a higher degree of cooperation than ordinarily aimed for in such instruments. Other terms might indicate that the parties sought to regulate only technical matters. Finally, treaty terminology might be indicative of the relationship of the treaty with a previously or subsequently concluded agreement.
The term "agreement" can have a generic and a specific meaning. It also has acquired a special meaning in the law of regional economic integration.
The term "charter" is used for particularly formal and solemn instruments, such as the constituent treaty of an international organization. The term itself has an emotive content that goes back to the Magna Carta of 1215. Well-known recent examples are the Charter of the United Nations of 1945 and the Charter of the Organization of American States of 1952.
The term "convention" again can have both a generic and a specific meaning.
The term "declaration" is used for various international instruments. However, declarations are not always legally binding. The term is often deliberately chosen to indicate that the parties do not intend to create binding obligations but merely want to declare certain aspirations. An example is the 1992 Rio Declaration. Declarations can however also be treaties in the generic sense intended to be binding at international law. It is therefore necessary to establish in each individual case whether the parties intended to create binding obligations. Ascertaining the intention of the parties can often be a difficult task. Some instruments entitled "declarations" were not originally intended to have binding force, but their provisions may have reflected customary international law or may have gained binding character as customary law at a later stage. Such was the case with the 1948 Universal Declaration of Human Rights. Declarations that are intended to have binding effects could be classified as follows:
An "exchange of notes" is a record of a routine agreement, that has many similarities with the private law contract. The agreement consists of the exchange of two documents, each of the parties being in the possession of the one signed by the representative of the other. Under the usual procedure, the accepting State repeats the text of the offering State to record its assent. The signatories of the letters may be government Ministers, diplomats or departmental heads. The technique of exchange of notes is frequently resorted to, either because of its speedy procedure, or, sometimes, to avoid the process of legislative approval.
A memorandum of understanding is an international instrument of a less formal kind. It often sets out operational arrangements under a framework international agreement. It is also used for the regulation of technical or detailed matters. It is typically in the form of a single instrument and does not require ratification. They are entered into either by States or International Organizations. The United Nations usually concludes memoranda of understanding with Member States in order to organize its peacekeeping operations or to arrange UN Conferences. The United Nations also concludes memoranda of understanding on cooperation with other international organizations.
A modus vivendi is an instrument recording an international agreement of temporary or provisional nature intended to be replaced by an arrangement of a more permanent and detailed character. It is usually made in an informal way, and never requires ratification.
The term "protocol" is used for agreements less formal than those entitled "treaty" or "convention". The term could be used to cover the following kinds of instruments:
The term “Parties", which appears in the header of each treaty, in the publication Multilateral Treaties Deposited with the Secretary-General, includes both "Contracting States" and "Parties". For general reference, the term "Contracting States" refers to States and other entities with treaty-making capacity which have expressed their consent to be bound by a treaty where the treaty has not yet entered into force or where it has not entered into force for such States and entities; the term "Parties" refers to States and other entities with treaty-making capacity which have expressed their consent to be bound by a treaty and where the treaty is in force for such States and entities.)
The term "treaty" can be used as a common generic term or as a particular term which indicates an instrument with certain characteristics.