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International Law: General Sources: U.S. practice of international law

This guide lists essential sources for researching general aspects of international law. For specialized topics, such as human rights and international arbitration, see the guide International Law: Specialized Sources.

What types of actions and documents show state practice and opinio juris?

Various research guides, books and articles provide lists of the types of state actions and documents that might be evidence of "state practice" and/or opinio juris. See Research strategies & selected books, e.g., Kuehl & O'Brien, International Legal Research in a Global Community, at 76.

Use the other tabs of this research guide to locate any specific sources that you need, e.g., sources for researching the practice of international lawtreatiescase law/jurisprudenceinternational organizations, etc.

For historical details and background, use The SHAFR Guide Online: An Annotated Bibliography of U.S. Foreign Relations since 1600, Brill Online. The Bibliography covers all historical periods, geographical areas and major themes. Materials listed include government documents, biographies, monographs, book chapters, journal articles, websites, etc.  

U.S. Department of State

The Digest of United States practice

The Department of State Office of the Legal Advisor publishes the Digest to provide a historical record of the views and practice of the government in public and private international law over a period of time. The editors cite, excerpt or reprint documents from the State department and other agencies and departments. The title of the series has changed over the years. 
Finding documents excerpted or cited in the digests:  The Digest now provides citations to internet or other publicly available sources of the full text. Starting with 1989, for documents excerpted or cited in the Digest that are not readily available in hard copy or electronic format, the Dept. of State website provides links to the full text (click on the link for the year). See also Foreign Relations of the United States, in the next box on this page 

FRUS, Foreign Relations of the United States, & other document sources

Foreign Relations of the United States (FRUS) contains "the official documentary historical record of major U.S. foreign policy decisions and significant diplomatic activity." It includes declassified documents from the presidential libraries, Depts of State and Defense, NSC, CIA, other agencies, and from private papers of officials. Starting with 1952 FRUS is arranged by presidency and geographically and topically within each presidency. Coverage begins with 1861. It is published with many years delay.