National Security Agency
The Gulf of Tonkin Incident, 40 Years Later
Briefing book · written 4 August 1964 · released 4 August 2004
Why this matters
Declassified documents showing how thin the evidence was for the second North Vietnamese 'attack' on U.S. destroyers on 4 August 1964, which justified the Tonkin Gulf Resolution and escalation in Vietnam. Signals intelligence and on-scene reports were misread or selectively used. A core case study in intelligence and the road to war.
Read the original
https://nsarchive2.gwu.edu/NSAEBB/NSAEBB132/
Hosted by National Security Archive (GWU)
Tags
Part of a collection · step 4 of 9
Cold War Signals Intelligence
When intercepts were misread, a war escalated.
Cite
National Security Agency. "The Gulf of Tonkin Incident, 40 Years Later." 4 August 1964. Released 4 August 2004. https://nsarchive2.gwu.edu/NSAEBB/NSAEBB132/ (accessed via The Quiet Archive, QA-0050).
Shelved nearby
- 1995 QA-0015NSA · Official history
American Cryptology during the Cold War, 1945–1989 (Thomas R. Johnson)
The NSA's own four-volume classified history of U.S. signals intelligence from the end of World War II to the fall of the Berlin Wall, by agency historian Thomas R. Johnson.
- 1992 QA-0137NSA · Correspondence
NSA records on the Pentagon's 1992 search for missing Cold War reconnaissance aircrews
Records released by the NSA in September 2025 and published in October 2026, detailing a 1992 Pentagon effort to work out whether crews of shot-down Cold War reconnaissance flights had been captured by the Soviet Union, China or others.
- 1969 QA-0016NARA · Report
Pentagon Papers: full declassified Report of the OSD Vietnam Task Force
All 47 volumes of the Defense Department's secret history of U.S. involvement in Vietnam, officially declassified and released in 2011, forty years after the leak.
- 1961 QA-0004CIA · Collection
President's Daily Brief, 1961–1969 (Kennedy and Johnson)
About 2,500 daily intelligence briefings written for Presidents Kennedy and Johnson, starting with the President's Intelligence Checklist first delivered on 17 June 1961.