Definition of a treaty

Legal assistance paper

All reasonable efforts have been made to ensure the accuracy of this information at the time the advice was produced (please refer to the date produced below). However, the materials have been prepared for informational purposes only and may have been superseded by more recent developments. They do not constitute formal legal advice or create a lawyer-client relationship. You should seek legal advice to take account of your own interests. To the extent permitted any liability is excluded. Those consulting the database may wish to contact LRI for clarifications and an updated analysis.

Date produced: 07/12/2009

1. What makes a text a “treaty”? 

2. And what distinguishes a “treaty” text from political agreements, COP/CMP Decisions, political agreements, road maps, accords, etc?

3. For example, does a treaty text require certain “final” provisions, e.g. on ratification? Does the wording of the provisions make a difference, e.g. binding “shall” provisions? It might be helpful to analyse this separately for the KP and the LCA tracks. For KP, what kind of text would be a valid amendment to the Kyoto Protocol with treaty status? For LCA (or a combined LCA-KP text), what kind of text would be valid for a treaty (under the UNFCCC)?


1. According to the Vienna Convention on the Law of Treaties, a treaty is ‘an international agreement concluded between States in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation.’ In theory, any draft text that is currently circulating in Copenhagen could become a treaty as long as the participating Parties have that intention. The decisive factor in determining whether an instrument is or is not a treaty is whether the instrument is intended to create legally binding obligations between the parties . The question of whether this is indeed the intention will be determined in the light of all the circumstances of the case. In some cases, the text of the instrument in question may make it clear that it is intended that the instrument is intended to form the basis of legally binding obligations. In other cases, the text may be framed in such a way as to indicate that it is simply intended as a statement of (non-binding) general principle. Where there is doubt as to whether or not it is intended that the instrument should lay down legal obligations, the determination lies within the competence of the interested state, subject to the duty to act in good faith. Intention takes precendence over form in cases of doubt.

It is important to remember that intention is decisive-states do not unintentionally adopt treaties. However, there may be room for argument about the legal status of certain texts: for example about the status of COP decisions (see earlier advice on this). There may also be room for argument as to the interpretation of a treaty, based on texts adopted by the parties on its conclusion or based on subsequent agreements or practice, as summarised below.

It may be that a text adopted by the Parties may affect the interpretation of an existing treaty. Article 31(1) of the Vienna Convention on the law of treaties provides that treaties must be interpreted in good faith in accordance with the ordinary meaning to be given to the terms of the treaty in their context and in the light of its object and purpose. ‘Context’ includes any agreement made by all the parties in connection with the conclusion of the treaty and any instrument made by one or more of the parties in connection with the conclusion of the treaty and accepted by the other parties as an instrument related to the treaty (Article 31(2)). Furthermore, subsequent agreement between the parties regarding the interpretation of the treaty and subsequent practice in the application of the treaty which establishes agreement between the parties regarding its interpretation may also be taken into account in interpreting a treaty, see Article 31(3) of the Vienna Convention. COP decisions may be relevant in this context, depending on the procedure for their adoption and any statements made by any Parties at the time of their adoption.

This means that there is scope for affecting the interpretation of a treaty through for example the adoption of COP decisions (this has been very important in the CITES regime for example)-each case must be considered on its owne terms in the light of the relevant treaty and the circumstances for the adoption of the decision in question eg voting, statements made etc.

2. A treaty is an instrument which is intended to create international legal rights and obligations. It can be distinguished from the examples provided as follows:
Political agreements: This covers a broad spectrum of agreements which can vary significantly in terms of their level of seriousness and enforceability. A treaty falls within this broader category – though by no means are all political agreements, treaties.
Road maps: Road maps represent a type of political agreement which may lack the legally binding quality of a treaty, depending on the intention of the parties which adopted it.
COP/CMP decisions: Whether such decisions have the binding quality of a treaty ultimately depends on the powers ascribed to the COP in the treaty text. The relevant treaties for the climate change negotiations (the UNFCCC and the Kyoto Protocol) do not contain provisions explicitly granting binding authority to the COP and CMP to take binding action in a specific instance. COP decisions may be relevant to the interpretation of the treaty in relation to which they are adopted (see above)
Accords: Accords are synonymous with treaties; there is no distinction between the two.

3. The specific wording of a text does not determine whether it constitutes a treaty. Rather, a text becomes a treaty if participating States intend that it should create international legal rights and obligations and then follow the correct procedures to bring it into force, as prescribed by international law (pending entry into force, the instrument is still a treaty).
For example, Article 20 of the Kyoto Protocol sets out the steps through which States may adopt amendments to the Protocol. These steps relate to process rather than the substance of the text (e.g., proposed amendments must be communicated at least six months prior to their adoption and must secure at least a three-fourths majority vote among the Parties). Amendment of the treaty is binding to the extent prescribed by the rules on amendment laid down in the treaty concerned e.g. as to the extent to which parties may opt out etc.