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International Law Research Guide: Treaties

A research guide to help researchers locate and understand public and private international law resources.

About Treaties

Treaties (also called covenants, protocols, acquis, conventions, pacts or charters) are international agreements between states and/or international organizations. Treaties are primary sources of international law.

Conventional international law is based on consent of state parties and as such treaties applies only between those consenting parties. In determining treaty application,

  • check to see which state parties have both signed and ratified the treaties
  • watch for state party reservations, understandings and declarations which can transform that state's obligations.

Treaties only bind nonparties when they form the basis for customary international law. Customary International Law is formed when states consistently act in a certain way (state practice) out of a sense of legal obligation (opinio juris). Evidence of state practice includes domestic legislation, regulations, treaties, judicial decisions, diplomatic communications, NGO and IGO practice (for example General Assembly Resolutions and state voting practice). Look at judicial decisions and executive communications for evidence of opinio juris. A state may escape the application of customary international law by being a persistent objector.

Important Treaty Related Research Tasks

Understand Treaties Generally

Find Secondary Sources Explaining how to Interpret Treaty Law

Find and Analyze Specific Treaties

Find Status Information about the Treaty

With regard to your treaty, you may need to know:
  • Who are the parties to the agreements (multilateral or bilateral), who has signed and who has ratified (agreed to be bound by) the treaty?
  • What are the effective dates of the treaty?
  • Have the parties made any reservations or declarations?
  • Have there been any modifications or updates to the treaty?

If there is an official website for the treaty, as there are with many major treaties, this information is usually found on that website. Otherwise, you can check a Treaty Index, or a database containing the full-text of the treaty.

Find the text of the treaty or agreement

Which source you will find most useful for locating the treaty text depends on what information you have about the treaty:

If you have a citation:
If you do not have a citation, but you know the topic, of your treaty, you have a few options to find your treaty.
If you know your topic and you know that the U.S. is a party, you can:
If you know your topic and you know that the U.S. is a party, you can:
Another option for finding U.S. Treaties, if you know the year that the treaty came into force:
Treaties used to found International Organizations are usually available on the official website for the organization.

Find National Legislation Implementing the treaty or related to the treaty topic

Find Judgments interpreting Treaties

Find Travaux préparatoires, to provide insight about the intent of the treaty negotiators

Find Secondary Sources Analyzing a specific Treaty

Law of Treaties

Use these resources to find Secondary sources to help you understand how to interpret treaties generally.

To understand Treaty Vocabulary, try these UN sources:

The Law of Treaties is embodied in the Vienna Convention on the Law of Treaties
You can use any of the full text treaty sources referenced below to find this treaty, but here is a direct link to an easy to read version.
For help understanding the Vienna Convention on the Law of Treaties, here is an Introductory note.

If you prefer to watch videos to learn more, explore the Lecture Series on this website.

Scholarly Articles on Treaty Law
This subject search in the MPEPIL takes you to a list of scholarly articles on the Vienna Convention on the Law of Treaties

Find Treaties using Treaty Indexes

A Treaty Index is a tool for finding treaties based on the involved parties, subject matter, dates of entry into force, or other related characteristics.

Online Treaty Indexes

Multilateral Treaty Index

U.S. Treaty Indexes, Bilateral and Multilateral

If the U.S. is a party to the treaty you can use these finding tool to get more information about the treaty, including some status information and citation(s) to the treaty that you can use in HeinOnline to pull up the full text.  

Print Treaty Indexes

Find Treaty Text By Citation

Find by Citation

Find U.S. Treaties by Topic in full-text databases

Find Bilateral and Multilateral Treaties between the US and other countries.
Use this U.S. Government database if you only know the topic of your treaty or have some of the treaty language. You can run a key word search.
Or use these subscription databases. You can browse or run key word searches in these databases to find treaties where the U.S. is a party. You can search for topics, or for specific treaty language.

In addition to these searchable full-text U.S. treaty sources within Lexis and Westlaw there are also topic specific sources.

Find U.S. Treaties with Sovereign Tribal Nations 

For Treaties between the U.S. and Tribal Governments, see:

For Analysis of Native American Treaties, see this select bibliography of Books about Treaties Between the United States and Sovereign Tribes.

Find Treaties by Topic Using Full-text Databases and Websites

Find Text of Bilateral and Multilateral Treaties

Topic Specific Databases and Websites

Some subscription databases and websites provide access to treaties on a specific topic.

Subscription Databases by Topic
Treaty Collection Websites Organized by Topic

The mission of the Council of Europe is to promote democracy, human rights and the rule of law across Europe and beyond. To that end, they maintain a website that provides access to their treaties related to these topics.

Use Treaties and International Acts Series to Find U.S. Treaties by Year

If you know the year that a treaty to which the U.S. is a party, came into force (information that you can get from the Treaties in Force document referenced above), you can use these U.S. Government official sources to find the full text of the treaty:

Find Foundational Treaties Used to Establish an International Body

Major Treaties used to found International Bodies, usually have their own websites, with the treaty text as well as status information and sometimes also domestic implementing legislation. A few examples are provided below, but this is not an exhaustive list. You can do a Web search for the International Body and then browse the website to looks for the founding documents or if you know the name of the treaty , you can do a Web search to see if there is an official website for the treaty. 

Westlaw also provides access to European Union Treaties.

National Implementing Legislation Databases

Nation State Legislation Implementing Treaty Law

There is no one database for the kinds of domestic legislation that implements treaty law. However, International bodies sometimes maintain a database of domestic laws implementing treaty law on specific topics.

The ICRC is an example of an organization that maintains a database of select legislation and case law implementing IHL treaties and other related international instruments. 

Court Decisions Interpreting Treaties or Related to Treaty Issues

Search in International Courts for Case Law Interpreting treaties

Some resources provide access to national case law on specific treaties or specific issues in international law.

Travaux Préparatoires

In the same way that you would use legislative history to interpret an ambiguous statute, you can consult Travaux préparatoires to interpret an ambiguous treaty. 

Sources of Travaux préparatoires include UN Materials documenting the treaty negotiation process. For some specific treaties, there may be online or print collections of Travaux préparatoires. You can do a web search to find online collections, although a few examples are provided below. For print collections, you can search the UC Law SF catalog, or WorldCat. Some sample searches as well as examples of travaux préparatoires in our collection for specific treaties are provided below.

Select Web Sources of Collections of Travaux Préparatoires

UN Materials

Secondary Sources and Commentary on Specific Treaties

For journal articles and books on specific treaties, please use these resources:

Within HeinOnline, you may find these specific resources useful:
For Additional Scholarly Articles on Treaties use