The War Powers Resolution of 1973 requires Presidents to notify Congress within 48 hours of sending U.S. armed forces into hostilities or certain other situations abroad, and to provide specific information about those deployments. These “48-hour reports” are a primary means for Congress to ensure transparency and create the possibility of meaningful oversight of the President’s use of U.S. armed forces abroad.
<< Starting at the center, hover over segments of the chart to explore the full universe of WPR “48-hour reports,” arranged by Presidential Term, Purpose/Mission, and Domestic Legal Authority.
The War Powers Resolution (WPR) is a landmark statute passed after the Vietnam War. Its aim is to restore the constitutional balance between Congress and the President in deciding when the nation goes to war. To create the transparency necessary for achieving this goal, the WPR requires the President to notify Congress within 48 hours of introducing U.S. armed forces into hostilities, deploying combat-equipped forces, or substantially enlarging those deployments (“48-hour reports”).
This project creates the first publicly accessible, searchable database analyzing the contents of all unclassified 48-hour reports submitted to Congress since the WPR was enacted over 45 years ago (more than 100 in total). The living database enables us to assess key questions about presidential exercise of war powers: Where and why are Presidents deploying armed forces abroad? How often do Presidents rely solely on their own constitutional authority to do so, and is that authority being stretched? Has reporting fulfilled the WPR’s requirements? In what ways are the WPR’s requirements insufficient to inform Congress of how the President is using our armed forces abroad, and in what ways is the WPR succeeding in providing meaningful transparency? Answers to these questions illuminated by this project will help lay the foundation for future study and reform.
Website data current through:
September 09, 2025
The WPR requires presidents to report “the circumstances necessitating the introduction” of armed forces. This chord diagram shows the stated purpose or mission of WPR-reported activity, broken down by administration.
<< Hover over a president’s name on the left side of the chord diagram to show a breakdown of their 48-hour reports by purpose/mission. Hover over a purpose/mission on the right side of the diagram to see how it maps across different presidential administrations.
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