Law of Treaties in the Modern World


When two or more nation states are engaged into international agreement or contract this agreement is often referred to as treaty. Treaty is arrived at by negotiations. When parties involved creating a treaty, it invokes obligations that are binding between these parties. It provides a clear cut of responsibilities and rights that each party is supposed to fulfill as agreed upon in the treaty. In the context of international law, this term encompasses number of international agreements. Nevertheless, the term can also be taken to mean any form of agreement especially between parties that are not nation states (National Treaty Support Group ATSIC, para. 2). The purpose of this paper is to define the term treaty, discuss functions of treaties and law of treaties.

Definition of treaty

According to Anthony Aust a treaty can concisely be defined as an international agreement which is concluded between the states in written form and is governed by international law (Aust, pp 14). A treaty is an international agreement which must possess an international attribute. In some constitution, treaties are given classes such as inter-governmental, inter-state or administrative treaties. However, according to Vienna Convention on the Law of Treaties of 1969 such categories of treaties are not acknowledged.

Another important feature in this definition of treaty is that treaty must be concluded between states. Aust maintains that if an agreement is between international companies or a company and a state such agreement cannot be considered to be a treaty. A good illustration for this is a case held by the Internationals Court of Justice involving oil dispensation to a certain foreign company. Because the state in which the company belonged was not party to the oil allowance, the agreement was not by any means a treaty (Aust, pp 16).

The third element of a treaty is that it should be in written form. In regard to the Vienna Convention on the Law of Treaties of 1969, oral agreements do not hold. However, treaty can be contained in form of telex, e-mail or fax message. In this respect provided such text can be turned into a readable and permanent form, it can be considered to be in written form. Even though original copies are not present but there is means of authenticating the signature, such agreements are still treaties.

Important thing is that such signature needs to be unique and associated with the signatory which identifies him. It should be created by means which is strictly under his control besides being connected to the source of data which would disclose alteration done by only one side or unilaterally (Aust, pp16-17). Lastly, an agreement to qualify to be a treaty must be governed by international law. Referring back to the commentary from International Law Commission, the clause ‘governed by international law’ indicates there is interest in creating legal obligations that are governed by international law. The absence of this element in an agreement makes it not to be considered to be treaty (Aust, pp 17).

The role of treaties

It is through treaties different states can be able to create international law. For any treaty to come into existence, it takes time and a lot of effort through negotiations. Treaties facilitate nation states to create particular obligations which are more likely to be honored. This is due to the fact that treaties are made through conscious deliberations and on basis of mutual understanding. These international agreements have come to be relevant sources of international law. When treaty come into existence after fulfilling formal requirements it enters into force (Rosenne, pp 188)

When a treaty enters into force it becomes a source of international law. Nevertheless, for a treaty act as a source of law, some principles govern it. First, principle is that every treaty is voluntary. This means that states which are party to the treaty have mutually accepted to be bound by it. This is exceptional as in some situations like territorial delimitation of boundaries. Second principle that governs treaty is that if a state sign to give consent to a treaty, such state become bound by the terms therein in the treaty and all parties to the treaty in question are all bound by equal magnitude.

For this reason, treaties act as sources of binding law only to the parties which have given the consent. But in case treaties entrench customary law into it, non-parties are not affected. This is due to the facts that those states which consider this customary law bidding to them, they are not bound by treaty simply because they are not part of the treaty. Lastly, if a treaty codifies customary law as in the Vienna Convention on the Law of treaties-Danube Dam Case, para.46, those substances included in the obligations in respect to the treaty applies to all states (Dixon, pp 26-28).

Law of treaties

According to Dixon the law of treaties refers to body of international law which provides procedures and substantive rules which govern how treaties should be used. These procedural and substantive rules that guide application of treaty address issues such as how treaty enters into force, its termination, interpretation as well as reservations (Dixon, pp53). Vienna Convention on the Law of Treaties provides that in Article 24, a treaty will come into force in a date it provide or agreed upon by the negotiating States. Unless treaty provides otherwise, a State is bound by the treaty on that date when it comes into force and on the ground that it consents to be bound by the treaty.

It further stipulates that the provisions which regulate authentication of text regarding the treaty itself, States consenting to be bound by the treaty, the date treaty enters into force and reservations among others things when treaty has not been into force all these only apply on the time when such text is adopted (Sinclair, pp 159). Concerning termination of the treaty, Article 43 provides that termination of treaty or withdrawal of a party to the treaty may take place only through the application of the provisions of the treaty or through present Convention (O’Brien, pp 351).

When it comes to interpretation of treaties, Article 31 indicates that it shall be done based on good faith. It further expounds that ordinary meaning should be given to treaty’s terms in the context and light of treaty’s object and purpose. In the same Convention Article 19 through 20 address matters regarding reservations. State in party of treaty is allowed to formulate reservations when accepting a treaty provided that treaty does not prohibit such reservations, treaty has specific reservations and the one in question is not included or the reservation is found to be incompatible with object and purpose of the treaty. Where a reservation is expressly allowed by the treaty, such reservation does on necessarily need acceptance by other States involved unless treaty provides so (Gehr, para. 1).

Examples of international treaties

One of the earliest treaties by beginning of nineteenth century is the Chinese Treaty between United State of America and Chinese government in 1904. The treaty was intended to promote commercial relations. The ratifications were exchanged at Washington where President Roosevelt proclaimed by signing to put treaty into effect. This was later followed by issue of statement from State Department explaining the benefit of treaty that it will help to insure the integrity of China and its administrative control in Manchurian provinces. Before that day, Chinese Government had exchanged a copy of treaty which was considered to be equivalent of delivering treaty document to the United State. After one year and half of negotiations, the treaty finally saw this light and was able to address issues of commerce, navigation and lifting restrictions that adversely affected both parties (Russell, pp 55).

Nuclear Arms Treaty between Russia and United States is one of the recent treaties in the last two decades. The key participants on this treaty were President Bush and President Vladimir V. Putin. Both President Bush and Putin agreed to reduce their nuclear arsenal by about two thirds over the period of ten years from then. This new treaty was considered to be unique from previous ones as it allowed United States and Russia to have freedom upon how they will operate their nuclear forces. It intended to bring to an end cold war between the two states (Goldgeier & Mcfaul, pp 80).


When two or more states get engaged into a form of agreement it may be termed as a treaty. However, for a treaty to be valid it should be an international agreement which has been concluded by states, be in a written form and governed by international law. Treaties forms sources of international law because they are law binding. Law of treaties is body of international law that contains procedure and substantive guidelines on how of treaties should be used. Such includes how treaty should enter into force, its interpretations, reservations and termination among other aspects that relate to it.

Work cited

Aust, A. Modern treaty law and practice. New York: Cambridge University Press, 2000

Dixon, M. Textbook on international law. Oxford: Oxford University Press, 2007

Rosenne, S. The law of treaties: a guide to the legislative history of the Vienna convention. Boston: Brill Archive, 1970

Gehr, W. The international law of treaties. 2009. Web.

Goldgeier, J. M, & Mcfaul, M. What to Do about Russia. Policy Review Journal, Vol. 11, 2001

O’Brien, J. International law. Oxford: Routledge Cavendish, 2001

National Treaty Support Group ATSIC. What is a treaty? 2009. Web.

Russell, G.Theodore Roosevelt’s Diplomacy and the Quest for Great Power Equilibrium in Asia. Presidential Studies Quarterly Journal, Vol. 38, 2008

Sinclair, I. M. The Vienna Convention on the Law of Treaties. London: Manchester University Press ND, 1984

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LawBirdie. "Law of Treaties in the Modern World." March 22, 2023.