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Public International Law: Treaties

This guide will help you find resources for researching public international law.

The Law of Treaties

The 1648 Peace Treaties of Westphalia established the framework for modern treaties and recognised the right of the sovereign to govern free from outside interference. 

The Vienna Convention on the Law of Treaties is the UN agreement that codifies the rules that guide treaty relations between States. The Convention provides an international legal framework for these relations in times of peace (the effect on treaties of the outbreak of hostilities between States is explicitly excluded from the reach of the Convention). This framework includes the rules on the conclusion and entry into force of treaties, their observance, application, interpretation, amendment and modification, and rules on the invalidity, termination and suspension of the operation of treaties. By providing this legal framework, the Convention promotes the purposes of the UN set forth in its Charter, including the maintenance of international peace and security, the development of friendly relations between states and the achievement of cooperation among nations. 

The treaty text may provide for the manner by which it takes effect. Generally, treaties will enter into force when it has been signed and ratified by a certain number of parties. Parties to a treaty may ratify a treaty with reservations or other declarations unless the terms of the treaty place restrictions on those actions. A reservation is a country's attempt to modify certain terms of the treaty, as it applies between itself and other countries.

Multilateral treaties are published in sets such as the United Nations Treaty Series (UNTS). Only treaties deposited with the UN Secretary General become part of the UNTS. Although most multilateral (and many bilateral) treaties are deposited with the UN as a matter of course, states are under no specific obligation to do so. A good source of information on the role of the UN as a treaty depository is the Summary of Practice of the Secretary-General as Depository of Multilateral Treaties on the UN website. 

Treaty information in online Encyclopaedias

Oxford Bibliographies - International Law  (UniMelb staff & student access) provides authoritative encyclopedic entries and annotated bibliographies on a range of topics such as the law of treaties and treaty interpretation.

Max Planck Encyclopedia of Public International Law (UniMelb staff & student access) provides comprehensive and authoritative overviews of all aspects of international law and is a great starting point for your research. Entries are arranged alphabetically by topic under broad subjects such as the law of treaties. From within each entry in the Encyclopaedia, the Oxford Law Citator will link to other relevant entries in the Encyclopaedia and to relevant decisions in international courts in the Oxford Reports on International Law. 

Citing Treaty Series - AGLC4 Style

If a treaty is included in a treaty series, the treaty series should be cited rather than eg: the UN document number. Treaties are often included in several treaty series. According to Chapter 7.4 (pp 125-127) of the Australian Guide to Legal Citation, treaties should be cited in the following preferential order:

1. Consolidated Treaty Series (ConTS) 1648-1919; League of Nations Treaty Series (LNTS) 1920-1944; or United Nations Treaty Series (UNTS) 1946+

  • The Law Library has the Consolidated Treaty Series (also known as Parry's Treaty Series) in print on level 4 and online, entitled Oxford Historical Treaties.

2. An official treaty series of a state party (for Australia, this is the Australian Treaty Series (ATS) or Australian Treaties Not Yet in Force (ATNIF))

3. Another international or regional treaty series (such as the European Treaty Series (ETS)) 

4. International Legal Materials (ILM) (University of Melb staff & students only). This series is on HEIN Online (vol 1, 1962+) in the Law Journal Library collection and in JSTOR (vol 1, 1962+) . This is not a treaty series - but it includes treaty texts and useful introductory information about the treaties, and it is an accepted method of citation.   Note that JSTOR's holdings are more up to date than HEIN.

5. If the treaty is not included in any of the above, use the official document number (such as a UN document number) to identify it, using the accepted style as described in Chapter 8 of ACLC4.

What is a Treaty?

Treaties are the principal source of Public International Law. 

The Vienna Convention on the Law of Treaties defines a ‘treaty’ as ‘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’ (Article 2(1)(a)).

A treaty is an agreement between sovereign States (countries) and in some cases international organisations, which is binding at international law. An agreement between an Australian State or Territory and a foreign Government will not, therefore, be a treaty. An agreement between two or more States will not be a treaty unless those countries intend the document to be binding at international law.

Treaties can be bilateral (between two States) or multilateral (between three or more States). Treaties can also include the creation of rights for individuals.

Treaties are commonly called 'agreements', 'conventions', `protocols' or `covenants' , and less commonly `exchanges of letters'. Frequently, `declarations'  are adopted by the UN General Assembly. Declarations are not treaties, as they are not intended to be binding, but they may be part of a process that leads ultimately to the negotiation of a UN treaty. Declarations may also be used to assist in the interpretation of treaties.

Drafting History Documents - Travaux Preparatoires

Travaux Préparatoires are official documents recording the negotiations, drafting, and discussions during the process of creating a treaty. These documents may be consulted and taken into consideration when interpreting treaties (Vienna Convention on the Law of Treaties, May 23, 1969, art. 32, 1155 UNTS 331). 

To find Travaux Préparatoires:

  • The Yale Law School Library has a useful website containing links to the full text of travaux préparatoires for many treaties.
  • The UN Audiovisual Library of International Law website lists many important treaties by topic - the treaty pages provide the full text of the treaties, travaux and related documents, information about the procedural history and useful introductory summaries.
  • For Travaux not available online, check the Library catalogue - many are available in print only and are published as books. For example, The Travaux Prèparatoires of the Crime of Aggression is available in the Law Library at  KC 218 A4 TRAV.

For more information on researching Travaux Préparatoires, see À la Recherche des Travaux Préparatoires: An Approach to Researching the Drafting History of International Agreements - from Globalex. 

Treaties Books & e-books

A selection of print and e-books held by the Law Library is listed below. More books on treaties can be found by searching the catalogue or browsing the shelves at KC 330.          

Open Access Articles on SSRN

Donaldson, Megan, 'The Survival of the Secret Treaty: Publicity, Secrecy and Legality in the International Order' (2017) University of Cambridge Faculty of Law Research Paper No. 56/2017

Finding Treaties

The Consolidated Treaty Series is a comprehensive collection of treaties of all nations concluded between 1648-1919. It is also known as Parry's Treaty Series and has been reproduced online as Oxford Historical Treaties (UniMelb staff and students) and is also available in print on Level 4 of the Law Library.

 The United Nations Treaty Collection website (open access) includes:

The UN Audiovisual Library of International Law (open access) website lists many important treaties by topic - the treaty pages provide the full text of the treaties, travaux and related documents, information about the procedural history and useful introductory summaries.

The UN Collection on HeinOnline (UniMelb staff & student access) includes the complete collection of the United Nations Treaty Series, the League of Nations Treaty Series, the Monthly Statement of Treaties & International Agreements.

The US Treaties and Agreements on Hein Online (UniMelb staff & student access)

Flare Index to Treaties (open access on the Institute of Advanced Legal Studies (IALS) website) - a searchable database of basic information on over 2,000 of the most significant multilateral treaties and some bilateral treaties concluded between 1353 and the present, with details of where the full text of each treaty may be obtained in paper and, if available, electronic form on the Internet.

WorldLII's International Treaties Collection (open access) includes the full texts of over 60,000 treaties (30,000+ from the United Nations collection) simultaneously searchable. They are both multilateral and bilateral (from numerous countries), in 27 databases from many sources, and from multiple LIIs.

World Treaty Index  (open access) - includes metadata for nearly 75,000 treaties that entered into force in the twentieth century. Users may search by numerous access points, including citation; title keyword; party name (including countries and organizations); subject; whether the treaty is bilateral or multilateral; and signature date.

International Law & World Order: Weston's & Carlson's Basic Documents (BRILL) (UniMelb staff & student access)

  • Includes the most significant and influential legal primary sources of the post-WWII global order. Arranged by topic and chronologically, the collection provides access to the laws of war; human rights; international trade, investment, and development; and environmental protection. Hundreds of key documents are presented in full text, with up-to-date information about the location and legal status of each document. Includes treaties, agreements, charters, concluding documents, conventions, covenants, decisions, declarations, draft articles, final acts, general acts, joint statements, manifestos, memoranda, pacts, procès-verbals, protocols, resolutions, rules, and statutes. 

Finding treaties by popular name

Treaties to which Australia is a party

The Australian Treaty Database (open access on the DFAT website) can be searched by subject and lists all bilateral and multilateral treaties to which Australia is a party, as well as information about the treaty process and adoption into domestic law.

The Australian Treaty Series website (open access on AustLII) lists all treaties to which Australia is a party and links to the full text - the treaties are listed chronologically and can also be searched by subject. In addition the Australian Treaties Library on AustLII links to other treaty resources such as links to treaties not yet in force, treaties under negotiation, and information about the adoption of treaties into domestic law - both the process and binding nature of the rights and obligations created by the treaty.

Treaty Research Guides & Tutorials

  • Treaties and international conventions - this open access tutorial from the Institute of Advanced Legal Studies by Lisa Davies covers the fundamentals of treaty research; finding treaties, checking status and party information, understanding treaty citations and tracing Travaux Preparatoires. It focuses on authoritative sources of treaties in print and online.