A treaty is a formal, legally binding written agreement between actors in
international law
International law (also known as public international law and the law of nations) is the set of rules, norms, and standards generally recognized as binding between states. It establishes normative guidelines and a common conceptual framework for ...
. It is usually made by and between
sovereign state
A sovereign state or sovereign country, is a polity, political entity represented by one central government that has supreme legitimate authority over territory. International law defines sovereign states as having a permanent population, defin ...
s,
but can include
international organizations
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 ...
, individuals,
business entities
In law, a legal person is any person or 'thing' (less ambiguously, any legal entity) that can do the things a human person is usually able to do in law – such as enter into contracts, sue and be sued, own property, and so on. The reason for ...
, and other
legal person
In law, a legal person is any person or 'thing' (less ambiguously, any legal entity) that can do the things a human person is usually able to do in law – such as enter into contracts, sue and be sued, own property, and so on. The reason for ...
s. A treaty may also be known as an international agreement, protocol, covenant, convention, pact, or exchange of letters, among other terms. However, only documents that are legally binding on the parties are considered treaties under international law. Treaties vary on the basis of obligations (the extent to which states are bound to the rules), precision (the extent to which the rules are unambiguous), and delegation (the extent to which third parties have authority to interpret, apply and make rules).
Treaties are among the earliest manifestations of
international relations
International relations (IR), sometimes referred to as international studies and international affairs, is the scientific study of interactions between sovereign states. In a broader sense, it concerns all activities between states—such as ...
, with the first known example being a border agreement between the Sumerian city-states of Lagash and Umma around 3100 BC. International agreements were used in some form by most major civilizations, growing in both sophistication and number during the
early modern era. The early 19th century saw developments in diplomacy, foreign policy, and international law reflected by the widespread use of treaties. The 1969
Vienna Convention on the Law of Treaties
The Vienna Convention on the Law of Treaties (VCLT) is an international agreement regulating treaties between states. Known as the "treaty on treaties", it establishes comprehensive rules, procedures, and guidelines for how treaties are defined ...
codified these practices, setting forth guidelines and rules for creating, amending, interpreting, and terminating treaties and for resolving disputes and alleged breaches.
Treaties are roughly analogous to
contract
A contract is a legally enforceable agreement between two or more parties that creates, defines, and governs mutual rights and obligations between them. A contract typically involves the transfer of goods, services, money, or a promise to tran ...
s in that they establish the rights and binding obligations of the parties. They vary significantly in form, substance, and complexity and govern a wide variety of matters, such as security, trade, environment, and human rights. Treaties may be bilateral (between two countries) or multilateral (involving more than two countries). They may also be used to establish international institutions, such as the
International Criminal Court
The International Criminal Court (ICC or ICCt) is an intergovernmental organization and international tribunal seated in The Hague, Netherlands. It is the first and only permanent international court with jurisdiction to prosecute individuals ...
and the
United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...
, for which they often provide a governing framework. Treaties serve as
primary sources of international law and have
codified or established most international legal principles since the early 20th century.
Notwithstanding the Law of Treaties and
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 ...
, treaties are not required to follow any standard form.
Nevertheless, all valid treaties must comply with the legal principle of ''
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 ...
'' (Latin: "agreements must be kept"), under which parties are committed to perform their duties and honor their agreements in
good faith. A treaty may also be invalidated, and thus rendered unenforceable, if it violates a
preemptory norm (''jus cogens''), such as permitting a war of aggression or crimes against humanity.
Modern usage and form
A treaty is an official, express written agreement that states use to legally bind themselves.
[Shaw, Malcolm. (2003). ] It is also the objective outcome of a ceremonial occasion that acknowledges the parties and their defined relationships. There is no prerequisite of academic accreditation or cross-professional contextual knowledge required to publish a treaty.
However, since the late 19th century, most treaties have followed a fairly consistent format. A treaty typically begins with a
preamble describing the "High Contracting Parties" and their shared objectives in executing the treaty, as well as summarizing any underlying events (such as the aftermath of a war in the case of a
peace treaty
A peace treaty is an agreement between two or more hostile parties, usually countries or governments, which formally ends a state of war between the parties. It is different from an armistice
An armistice is a formal agreement of warring ...
). Modern preambles are sometimes structured as a single very long sentence formatted into multiple paragraphs for readability, in which each of the paragraphs begins with a
gerund
In linguistics, a gerund ( abbreviated ) is any of various nonfinite verb forms in various languages; most often, but not exclusively, one that functions as a noun. In English, it has the properties of both verb and noun, such as being modifiable ...
(desiring, recognizing, having, etc.).
The High Contracting Parties—referred to as either the official title of the
head of state
A head of state (or chief of state) is the public persona who officially embodies a state Foakes, pp. 110–11 " he head of statebeing an embodiment of the State itself or representatitve of its international persona." in its unity and l ...
(but not including the personal name), e.g. ''His
Majesty
Majesty (abbreviated HM for His Majesty or Her Majesty, oral address Your Majesty; from the Latin ''maiestas'', meaning "greatness") is used as a manner of address by many monarchs, usually kings or queens. Where used, the style outranks the st ...
The King of X'' or ''His
Excellency
Excellency is an honorific style given to certain high-level officers of a sovereign state, officials of an international organization, or members of an aristocracy. Once entitled to the title "Excellency", the holder usually retains the right ...
The President of Y'', or alternatively in the form of "'' Government of Z''"—are enumerated, along with the full names and titles of their
Plenipotentiary
A ''plenipotentiary'' (from the Latin ''plenus'' "full" and ''potens'' "powerful") is a diplomat who has full powers—authorization to sign a treaty or convention on behalf of his or her sovereign. When used as a noun more generally, the word ...
representatives; a
boilerplate clause A boilerplate clause is a legal English term that is used in conjunction with contract law. When forming contracts, parties to the contract often use templates or forms with boilerplate clauses ( boilerplate language, used as standard language). Suc ...
describes how each party's representatives have communicated (or exchanged) their "full powers" (i.e., the official documents appointing them to act on behalf of their respective high contracting party) and found them in good or proper form. However, under the
Vienna Convention on the Law of Treaties
The Vienna Convention on the Law of Treaties (VCLT) is an international agreement regulating treaties between states. Known as the "treaty on treaties", it establishes comprehensive rules, procedures, and guidelines for how treaties are defined ...
if the representative is the head of state,
head of government
The head of government is the highest or the second-highest official in the executive branch of a sovereign state, a federated state, or a self-governing colony, autonomous region, or other government who often presides over a cabinet, a gro ...
or
minister of foreign affairs
A foreign affairs minister or minister of foreign affairs (less commonly minister for foreign affairs) is generally a cabinet minister in charge of a state's foreign policy and relations. The formal title of the top official varies between cou ...
, no special document is needed, as holding such high office is sufficient.
The end of the preamble and the start of the actual agreement is often signaled by the words "have agreed as follows".
After the preamble comes numbered articles, which contain the substance of the parties' actual agreement. Each article heading usually encompasses a paragraph. A long treaty may further group articles under chapter headings.
Modern treaties, regardless of subject matter, usually contain articles governing where the final authentic copies of the treaty will be deposited and how any subsequent disputes as to their interpretation will be peacefully resolved.
The end of a treaty, the
eschatocol
An eschatocol, or closing protocol, is the final section of a legal or public document, which may include a formulaic sentence of appreciation; the attestation of those responsible for the document, which may be the author, writer, countersigner, ...
(or closing protocol), is often signaled by language such as "in witness whereof" or "in faith whereof", followed by the words "DONE at", then the site(s) of the treaty's execution and the date(s) of its execution. The date is typically written in its most formal, non-numerical form; for example, the
Charter of the United Nations
The Charter of the United Nations (UN) is the foundational treaty of the UN, an intergovernmental organization. It establishes the purposes, governing structure, and overall framework of the UN system, including its six principal organs: the ...
reads "DONE at the city of San Francisco the twenty-sixth day of June, one thousand nine hundred and forty-five". If applicable, a treaty will note that it is executed in multiple copies in different languages, with a stipulation that the versions in different languages are equally authentic.
The signatures of the parties' representatives follow at the very end. When the text of a treaty is later reprinted, such as in a collection of treaties currently in effect, an editor will often append the dates on which the respective parties ratified the treaty and on which it came into effect for each party.
Bilateral and multilateral treaties
Bilateral treaties
Bilateral may refer to any concept including two sides, in particular:
*Bilateria, bilateral animals
*Bilateralism, the political and cultural relations between two states
*Bilateral, occurring on both sides of an organism ( Anatomical terms of l ...
are concluded between two states or entities.
[Nicolson, Harold. (1934). ''Diplomacy,'' p. 135.] It is possible for a bilateral treaty to have more than two parties; for example, each of the bilateral treaties between
Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...
and the
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...
(EU) has seventeen parties: The parties are divided into two groups, the Swiss ("on the one part") and the EU and its member states ("on the other part"). The treaty establishes rights and obligations between the Swiss and the EU and the member states severally—it does not establish any rights and obligations amongst the EU and its member states.
A
multilateral treaty
A multilateral treaty is a treaty to which two or more sovereign states are parties. Each party owes the same obligations to all other parties, except to the extent that they have stated reservation (law), reservations. Ex