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America's Wars, Causes of

A guide to resources for the study of causes or origins of America's major armed conflicts.


This guide is concerned with identifying as much as possible the origins or causes of America's major, armed, international conflicts.  It does not attempt to explore the execution, conclusion or implications of these wars nor does it attempt to address the myriad of lesser (for the U.S. military) conflicts both domestic and foreign.

For a convenient listing of such conflicts see  Wikipedia's entries for List of wars involving the United States at or Timeline of United States military operations at


The guide for each conflict includes the following subdivisions with content specific to the conflict:

  • Terminology
  • Reference Sources
  • Search Suggestions
  • Primary Sources

Reference Sources


War, Conflict, Violence and Peace

U.S. Foreign Affairs, Politics, Society, Security & the Military

Article Databases

Best Bets


Current Popular Opinion and Analysis

Historical Popular Opinion and Analysis

The Reader's Guide "Family" of Indexes of Popular and Scholarly Articles

Primary Sources: Definitions

While reference tools and secondary sources (scholarly books and journal articles) are essential for the scholar, his or her focus for original research will be primary sources. A primary source was created near in time and/or place to the event, activity, movement or subject under study. The closer in time and space to the event a source was created, the more likely a source will be considered primary.

Examples of Primary Sources
  • letters, correspondence and diaries
  • official documents, diaries, memoirs, correspondence
  • notes from interviews
  • posters, art & music
  • oral history
  • newspaper and periodical articles, ads, editorials, letters to the editor, etc.
  • any publication, document or item created contemporaneously with an event is potentially a primary source.

While the gold standard for primary sources is still the original document in its original format (e.g., actual letters, diaries, print newspapers, etc.), more and more primary sources have been microfilmed or digitized and subsequently made available in subscription databases or freely on the web. If you are using a digitized document, be sure to determine if the full document is included or only selected portions.  Selection involves value judgments and potential bias.

For other collections of primary source held by Notre Dame:
  • Use the ND Catalog
  • Advanced Search
    • Any
      • Contains
      • [ your search terms ]
      • AND
    • Any
      • Contains   
      • (cause* OR origin OR origins OR sources OR documents)

See  the "American Memory" project at the Library of Congress Collections for examples.

Primary Sources: Newspapers

Center for Research Libraries (CRL)

  • Has back files of non-U.S. newspapers
  • Will loan originals and microfilmed copies of substantial runs
  • Responds quickly to requests
  • Allows extended loan periods
  • Holdings are being added to the ND Catalog
Armed Conflicts before 1952
Armed Conflicts, 1941-2013
Armed Conflicts, 1980 --

Primary Sources: U. S. Federal Government Documents

Formerly classified (secret), now declassified (available) government documents (Post WWII)

Primary Sources: United Nations