Nuclear Strategy and Weapons

Washington, D.C., December 17, 2024 - A recently declassified Joint Atomic Energy Intelligence Committee (JAEIC) report from December 1960 is the first and only known U.S. intelligence report to correctly and unequivocally state that Israel’s Dimona nuclear project would include a reprocessing plant for plutonium production and was weapons related. All known, subsequent U.S. intelligence products treated the reprocessing issue as unsettled until the late 1960s, when Israel reached the threshold of a nuclear weapons capability and the U.S.

Washington, D.C., August 8, 2024 – On the week of the 79th commemoration of the U.S. atomic bombings of Hiroshima and Nagasaki, Japan, the National Security Archive today publishes a fascinating new collection of papers from the office files of Leslie Groves, the director of the Manhattan Project, the U.S. effort during World War II to develop and produce the world’s first nuclear weapons.

Washington, D.C., July 16, 2024 - On 16 July 1945, 79 years ago, the United States, under the Manhattan Project, staged the first test of a nuclear weapon in the New Mexican desert. The first trial of a plutonium implosion weapon, the explosion on the ground produced radioactive fallout contaminating over 1,100 square miles of the state, although some debris spread as far north as Canada.

Washington, D.C., May 31, 2024 - On 6 October 1977, President Jimmy Carter and top U.S. national security officials dialed into a secret “Missile Attack Conference” (MAC) to coordinate a response to a simulated surprise nuclear strike on the United States. Organized by the Joint Chiefs of Staff (JCS), the mock war scenario was the first to involve the U.S. President and may have prompted Carter to authorize a retaliatory nuclear missile launch, according to documents posted today by the National Security Archive. 

Washington, D.C., February 29, 2024 - Seventy years ago, on 1 March 1954 (28 February in Washington), the U.S. government detonated a thermonuclear weapon, code-named “Shrimp,” on Bikini Atoll in the Marshall Islands in what turned out to be the largest nuclear test in U.S. history. The Bravo detonation in the Castle test series had an explosive yield of 15 megatons—1,000 times that of the weapon that destroyed Hiroshima and nearly three times the six megatons that its planners estimated.

Washington, D.C., September 21, 2023 – The Reagan administration rejected an international agreement on humanitarian laws of war—Additional Protocol I to the 1949 Geneva Conventions—due to insurmountable objections from the Pentagon and the belief that it favored terrorists, according to a collection of declassified documents posted today by the National Security Archive.

Washington, D.C., July 18, 2023 – A set of highly secret emergency action plans kept inside the closely guarded “Football” that traveled with the President at all times and that would give the federal government sweeping emergency powers were of “doubtful legality,” “badly out of date,” and “even illegal,” according to top government officials whose views are memorialized in declassified records posted today by the National Security Archive.

Washington, D.C., June 6, 2023 - U.S. officials and NATO allies feared that international talks meant to strengthen the protection of civilians during conflicts could lead to a ban on the use of nuclear weapons, according to a September 1975 memorandum by the Pentagon’s Joint Staff posted today by the National Security Archive. Published as part of a new Electronic Briefing Book on the negotiations that produced Additional Protocol I to the 1949 Geneva Conventions, the Defense Department memo reveals some of the concerns that underlay the initial U.S.