An Introduction to Sources for Treaty Research

By Mark Engsberg

Mark Engsberg has been the Foreign and International Law Librarian at the Lillian Goldman Law Library, Yale Law School in New Haven, Connecticut since 2001.  He has recently been promoted to Head of Reference.  He holds a law degree from Willamette University College of Law in Salem, Oregon, a Masters and PhD in English from the University of Illinois at Urbana-Champaign, and a Masters in Library and Information Science, also from the University of Illinois. 

Published March 2006
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Table of Contents

A.        Introduction

This brief guide provides a broad overview of the sources necessary or helpful to conduct treaty research.  It covers background and definitional issues.  It is not meant to be a “how to” guide, rather it provides a description of the tools necessary for researching both bilateral and multilateral treaties.  This guide mostly covers information for researching treaties to which the United States is a party, but it also includes information useful for researching treaties to which the United States is not a party. 

The first portion of the guide contains information about treaties, locating treaties, finding aids for treaty documents and other related matters.  The final segment of the guide provides an overview of electronic sources for conducting treaty research. 

B.        Treaties and International Agreements

What is a treaty?  A treaty is a “formally signed and ratified agreement between two nations or sovereigns.”[1]  It is a record of the terms of agreement between two or more countries, and is governed by international law.  But, treaties or treaty-like instruments go by many other names as well, such as:

·       Accords

·       Pacts

·       Conventions

·       Agreements

·       Covenants

·       Final Acts

·       Charters

·       Protocols

·       Constitutions for international organizations

Regardless of the various terms used to describe them, apart from some minor differences, they are all basically the same thing.[2]

A treaty binds only the parties to the treaty.[3]  The US government is bound by the provisions of a treaty only when the agreement has been submitted to the US Senate for advice and consent and 2/3 of the Senate vote to approve it and the President ratifies it.[4]  The entire process is called ratification.

International agreements are sometimes confused with treaties, though they are not treaties.  Rather, they are executive in nature, can be approved with a simple majority vote of both houses of Congress, or may not even be submitted to Congress for approval.  These documents directly govern or implement a great deal of US foreign policy, especially matters related to trade.  International agreements are often preferred by various parties because they are often easier and more expeditious to obtain.  After all, a 2/3 majority in the Senate – the proportion necessary to ratify a treaty – can be very difficult to achieve.[5] 

C.         A Brief Treaty Lexicon

When working with treaties, it is important to have a basic understanding of several key terms.  As with many areas of the law and legal research, there is a specialized vocabulary, knowledge of which is essential for competent research and full understanding of treaty documents.[6]  Below is a quick guide to some of the more important terms, or those terms one most frequently encounters in treaty research:

·       Accession – formal adoption of the provisions of a treaty already agreed upon by other nations.[7]

·       Bilateral – a treaty between just two countries.[8]

·       Enter into force – when the terms of a treaty become binding on a party.  A treaty does not necessarily enter into force when the treaty is signed, or even when it is ratified, but it enters into force when parties agree that the treaty enters into force (“enter into force” is a concept usually associated with a specific date and time).[9]

·       International Agreements – international agreements are not treaties, but are treaty-like.  They do not require Senate ratification.  The United States says international agreements are not governed by international law.  The UN says international agreements are governed by international law.  Most of the United States’ formal relations with other countries are governed by international agreements.  In the US, there are currently about 4000 IAs in force and only about 400 treaties in force now where the United States is a party.[10]

·       Multilateral – a treaty between more than two countries.[11]

·       Parties – countries that have ratified a treaty; parties are bound by the terms of the treaty.[12]

·       Ratification – a country’s internal confirmation or acceptance of terms of a treaty agreement, usually accomplished through some form of legislative process.[13]

·       Reservation – a term or terms of a treaty objected to by a country.[14]  A country will formally declare it will not be bound by the objectionable term or terms of a treaty usually during the ratification phase.

·       Signatories – countries that have signed a treaty.[15]  Signing a treaty indicates intent to be bound by the terms of the treaty, but is not necessarily the same as actual accession.

D.        Locating Treaty Texts

There is no single correct way to do treaty research, but once one has become acquainted with the principal terms and sources of treaty documents it becomes a relatively simple matter to locate the text of a treaty.  It can be a bit more difficult to discover the current status of a particular treaty.  And it can be quite a challenge to find information about the negotiation or legislative history of a treaty, travaux preparatoire (unless the US is a party and you’re interested only in the US Senate ratification process).[16] 

So where does one locate the text of a treaty or agreement?  Where can one find the status and ratification information about a treaty?  Sources for Locating a Treaty Text where the United States is a party include the following:

·       United States Statutes at Large – contain US treaties until 1948

·       Treaties and Other International Agreements of the US 1776-1949 (Bevans)

·       In 1950, this became the official source of all US treaties and agreements

·       Volumes are published annually, each with a subject and country index

·       There is an unfortunate 8-10 year lag in publishing

·       Treaties and Other International Acts Series (TIAS) 1946-present

·       Treaties first appear in slip form in the TIAS

·       There is a publishing lag time of 5-6 years

·       Before ratification but before publication in TIAS, some treaties can be found in the Senate Document Series

There are many finding aids for treaties to which the US is a party.  Here are six of the most important ones, along with a brief description of the salient features of each resource:

1.     Treaties in Force (TIF)

·       Covers treaties from 1950 to present

·       Annual publication

·       Arranged by country and subject

·       Gives references to UST and TIAS numbers

·       Use it to verify the existence of a treaty

·       Available for free on the US Department of State web site

2.     A Guide to U.S. Treaties in Force

·       1982-present

·       use with TIF

3.     Guide to U.S. Treaties in Force: Current Treaty Action Supplement

·       Use with TIF and Guide to U.S. Treaties in Force

4.     U.S. Treaty Index

·       Currently contains 17 volumes and 2 supplements

·       Replaces, in its entirety, the former UST cumulative indexing service, which began in 1973.

·       Beginning with 2001 revised volumes, date coverage expands: 1776-2000 consolidation.

·       Consists of: Master guide (numerical), chronological index, country index, subject index, and geographical subject index.

·       Kept up to date by supplements, revised volumes, and Current treaty index.

5.     Current Treaty Index

·       Cumulative index to the United States slip treaties and agreements; and Treaties and agreements not published in TIAS.

·       Volumes for 1982- include information on TIAS.

·       Issues for 1982-1999 also known as 1st through 24th editions.

·       Companion service to The United States Treaty Index: 1776-… consolidation, and its supplements.

·       Updates the UST cumulative indexing service.

·       Changed to loose-leaf format in 1999.

6.     Index to International Treaties & Agreements

·       This index covers in-force treaties and agreements from 1783 to present.

·       Available in electronic format as part of the Oceana Online Web site, TIARA.

·       Known as Treaty and International Agreements Online.

For treaties to which the US is a party, one should consult one or more of the following to locate information on the treaty’s status, updating a treaty, and ratification of a treaty:

1.     TIF

2.     Guide to TIF

3.     CCH Congressional Index

4.     Current Treaty Index

5.     Senate Website

6.     Shepard’s U.S. Citations Note: pre-1950 treaties are listed by their Statute at Large # and post-1950 treaties are listed by their UST or TIAS #s.

7.     Some treaty secretariats have web sites that might provide status info

8.     Department of State Office of Treaty Affairs may be able to help (202) 647-1345.

Keep in mind that treaties which have not been ratified do not necessarily die at the end of a US congressional session – they frequently carry over to subsequent sessions.

E. Multilateral Treaties

The following sources are helpful for locating the text of multilateral treaties:

1.     Multilateral Treaties: Index & Current Status

·       Kept up to date by cumulative pamphlet supplements

2.     Multilateral Treaty Calendar 1648-1995

·       Current to 1995

3.     Status of Multilateral Treaties Deposited with the Secretary General

·       Includes status and reservation information

·       For the texts of these agreements, refer to the United Nations Treaty Series

·       Available in print and electronic formats

·       Print begins in 1981; current to 2002

·       The electronic version is a huge UN database United Nations Treaty Series

·       UN Charter requires member nations to register their bilateral or multilateral treaties with the UN.

·       UNTS is still the most complete list

5.     Other multilateral treaty series include:

·       League of Nations Treaty Series

·       Organization of American States Treaty Series

·       Pan American Union Treaty Series

·       European Conventions and Agreements (also known as European Treaty Series)

Europe – EU foundation treaties available online.  Treaties the EU has entered into as a party are also published in the Official Journal of the European Communities (OJ), L Series.  These are available in electronic form from 1998 to the present. 

International Legal Materials (ILM) – The ILM has been published since 1962.  It is a useful source for draft treaties, new, or unusual treaties.  It is available in electronic format on Lexis and Westlaw.

To find the status of a multilateral treaty, a good place to begin is with the Multilateral Treaties Deposited with the Secretary General.  This is a print product, but is also available online. 

Finding the reservations of parties to a multilateral treaty can be a really tough job.  Reservations often arise during the ratification process, and so they can be discovered in legislative histories (if any exist).  For European treaties, one should consult the European Treaty Series.  In the US, reservations can typically be found in the Congressional Record.  For other countries, a researcher may need to contact a given country’s diplomatic mission for information about that country’s reservations for a specific treaty.

To learn about the ratification process or status of a treaty, remember that a country may be a signatory but not ratify a treaty.  To determine the process of ratification outside the US, there are two main resources:

1)     National Treaty Law and Practice – also available through HeinOnline.

2)    Parliamentary Participation in the Making and Operation of Treaties, a Comparative Study

Most modern multilateral treaties create an administrative body called a secretariat.  The secretariat is charged with the administration of the terms of the treaty.  Secretariats can be useful sources for information relevant to treaty research. The secretariat is generally charged with:

·       Holding the text of the treaty

·       Tracking signatures

·       Tracking accession and ratification

·       Monitoring compliance

Many secretariats have their own websites with links to important treaty documents and other information.[17]  These websites are easily found using a general search engine. 

F. Bilateral Treaties – US Not a Party

Researching bilateral treaties where the US is not a party can be very challenging indeed.  First of all, every country deals with its bilateral treaties differently.[18]  Perhaps the easiest way to find these treaty documents is in a commercial compilation of bilateral treaties by subject.  Unfortunately, there are only a few of these, and these are focused almost exclusively on investment and tax treaties.  Three of these come to mind here:

·       Investment Promotion and Protection Treaties (from 1983) (Oceana)

·       Diamond’s International Tax Treaties of All Nations (Oceana) (the original 55-volume set is now available in a searchable electronic format)

·       The World Treaty Index (ceased publication in 1980; begins with League of Nations.  There is an electronic version of this index found at ).[19]  

Some government websites publish indexes to treaties or the full texts of treaties.  Australia and the Netherlands have complete treaty information for those countries.  Keep in mind that diplomatic missions of countries can also provide treaty information, so if one is having trouble locating the text of a bilateral treaty to which the United States is not a party, one could contact the official representative(s) of the government in question.  A place to find contact information for embassies or consulates is

For treaties to which the US is a party that you cannot find in other sources, you can contact the country desk at the Department of State or Department of Commerce. 

G. Electronic Resources for Treaty Research

This guide concludes with a very brief survey of some of the more important electronic resources for treaty research.  While I have included links to the electronic platforms for a number of resources listed above, what follows is a listing of materials that did not easily fit into the descriptions or organizational scheme above.  Electronic access to important legal information of all kinds is becoming more prevalent every day.  This is particularly true with respect to international treaty information.  Because of the dynamic nature of the digital world of treaty information, the following section does not pretend to be comprehensive, and I am sure the guide overlooks any number of excellent electronic resources.  I strive merely to represent the nature and variety of electronic resources for treaty information.

United Nations and United States treaty sources are perhaps the easiest to find in electronic formats.  In fact, it is probably fair to say that the UN is the leader in electronic access.[20]  Below is a sampling of several free Internet resources for treaty information.  Included in this section are resources for United Nations treaties, United States treaties, European and Organization of American States treaties.  The final section contains information about several subscription or proprietary databases, excluding Lexis and Westlaw. 

1. Free Internet Resources

UN Official Document System

·       Full-text database

·       Search engine retrieves documents only from the UN Documentation database (documents and preliminary versions of UN resolutions)

·       Simple and advanced search capabilities, including full text search.  Full text searches will often result in the most hits.

·       Contains a very helpful UN Documents Research Guide

Statutes at Large

  • Currently contains volumes covering the years 1789-1875, volumes 1-18. 
  • Statutes at Large ceased publishing US treaties in 1948. 
  • This is a good source for older US/Native American treaties.

US Department of State

  • Limited quantity, but what’s there is free and available in full text
  • No quick link to treaties on the home page; use the search function to locate treaties

US Trade Representative

  • Site contains the text of many US trade agreements and treaties
  • Includes global, regional, and bilateral trade agreements and/or links to secretariats, organizations, or other related documentation

Other sites to consider

Broadcast Method

Use,,, or any other search engine to locate treaties.  This is the most imprecise method, and you need to be particularly mindful of the varied quality of the sources you get from this kind of search.  A general search for “treaty” on Google currently results in over 56,300,000 hits.  Most of these sites are worthless, but some may be quite helpful.  Use the advanced search tool to help focus your search. 

2. Subscription Databases

United Nations Treaties

·       Huge full text database of UN treaties

·       Many helpful indices and tools

·       Use the help menus!

·       Advanced and Basic search options

·       The advanced search option contains very useful menus of “International Agreements by Popular Name,” “subject,” “Participants,” and other limiting factors.

·       Somewhat awkward navigation and viewing interface.

Access UN

·       Premier index to UN documents, including Official Records, masthead documents, draft resolutions, meeting records, UN Sales Publications, and the UN Treaty Series citations.  Also included is the full text records of thousands of UN documents.

·       Permits searching in multiple fields (e.g. subject, country, document number, etc.)

·       You can limit the search to full text documents, or by date ranges

·       The help menu is very helpful indeed.


·       HeinOnline uses a stable, reliable platform

·       Contains full text images of several key treaty research tools (e.g. Bevans)

·       Full text documents available only as an image (PDF)

·       Not 100% complete or current, but they’re adding more all the time

·       Not easily searchable; best for KNOWN ITEM searches (i.e. when you have the cite).

·       This includes the full text of the Statutes at Large from 1789-2002.  HeinOnline is providing electronic access to Indian treaties (1778-1842) and treaties between the U.S. and foreign nations (1778-1845), and treaties and other international agreements through 64 Stat. (1950). 

·       Other sources of U.S. treaties are available in HeinOnline’s Treaties and Agreements Library

Oceana Online – U.S. Treaties Researcher

·       Full text database of more than 11,000 US treaties and international agreements in force, plus 1,800 bilateral tax treaties from 185 countries

·       Covers 1783 to present

·       You can search by country, subject, or treaty name

·       You can easily cut and paste entire treaties or a few paragraphs into your word processor. 

[1] Black’s Law Dictionary, 1507 (7th ed. 1999).

[2] See,, which explains the fine distinctions between these treaty-like instruments.

[5] See for a more complete description of the difference between treaties and international agreements. 

[6] See, for a fuller description of treaty terms. 

[7] Black’s Law Dictionary, 13 (7th ed. 1999).

[8] Id, 155.

[10] See for a more complete description of the difference between treaties and international agreements. 

[11] Black’s Law Dictionary, 1036 (7th ed. 1999).

[12] Id, 1144.

[13] Id, 1269.

[14] Id,1309.

[15] Id, 1387.

[16] See Jonathan Pratter’s excellent guide to travaux preparatoire on Globalex, at Travaux_Preparatoires.htm

[17] See, for example the website for the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES),

[18] Stephanie Weigmann has created a very useful guide for locating treaties where the US is not a party.  Her guide can be found at

[19] The site is administered by Glenda Pearson at the University of Washington.  According the to the site, The World Treaty Index provides access to over 55,000 treaties of the 20th century, from sources ranging from the United Nations Treaty Series to various national indexes, gazettes, and official files.

[20] UN treaty documents are typically found in all six official languages: Arabic, Chinese, English, French, Russian, and Spanish.