On August 6 and 9, 1945, the cities of Hiroshima and Nagasaki were destroyed by the first atomic bombs used in warfare.
Documents on the decision to use the atomic bomb are reproduced here in full-text form, and many also as images. All transcriptions are by Gene Dannen. In most cases, the original documents are in the U.S. National Archives. Other aspects of the decision are shown from accounts by the participants. This page was new May 29, 1995, and it was last updated January 25, 2018.
International Law - Bombing of Civilians
- At the beginning of World War II, the bombing of
civilians was regarded as a barbaric act. As the war continued,
however, all sides abandoned previous restraints. But international law has
always distinguished between civilians and combatants. Legal
context to the decision, from a variety of international
treaties and the 1996 World Court opinion.
Target Committee, Los Alamos, May 10-11, 1945 - Minutes of the Target Committee, meeting in the office of J. Robert Oppenheimer, as they decided the best use of the “gadget.”
The Franck Report, June 11, 1945 - The Franck Report, written by a seven-man panel of scientists at the University of Chicago, urged that the bomb be demonstrated “before the eyes of representatives of all United Nations, on the desert or a barren island.”
Scientific Panel, June 16, 1945 - Despite the arguments against using the bomb made by the Franck Report, a panel composed of Oppenheimer, Fermi, Compton, and Lawrence found “no acceptable alternative to direct military use.”
Bard Memorandum, June 27, 1945 - Undersecretary of the Navy Ralph A. Bard wrote that use of the bomb without warning was contrary to “the position of the United States as a great humanitarian nation,” especially since Japan seemed close to surrender.
Setting the Test Date, July 2, 1945 - President Truman had delayed his meeting with Stalin until the atomic bomb could be tested. On July 2, General Groves told Robert Oppenheimer that the test date was being set by “the upper crust.”
Szilard Petition, first version, July 3, 1945 - The first version of Leo Szilard’s petition called atomic bombs “a means for the ruthless annihilation of cities.” It asked the President “to rule that the United States shall not, in the present phase of the war, resort to the use of atomic bombs.”
Petition cover letter, July 4, 1945 - Szilard sent copies of the July 3 version of his petition to colleagues at Oak Ridge and Los Alamos. This cover letter discussed the need for scientists to take a moral stand on the use of the bomb.
Groves Seeks Evidence, July 4, 1945 - As Szilard circulated his petition, General Groves sought ways to take action against him. On July 4, 1945, Groves wrote to Lord Cherwell, Winston Churchill’s science advisor.
Oak Ridge petition, July 13, 1945 - The first version of Szilard’s petition inspired a similar petition at the Manhattan Project laboratory at Oak Ridge, Tennessee. The names of the 18 signers are included.
Oak Ridge petition, mid-July 1945 - Another petition at Oak Ridge called for the power of the bomb to be “adequately described and demonstrated” before use. The names of the 67 signers are included.
Trinity Test, July 16, 1945 - Radiation Monitoring - The test of the atomic bomb in the New Mexico desert on July 16 was a spectacular success. This report by Manhattan Project Chief of Medical Section Stafford Warren shows that radioactive fallout from the test was an important concern.
Trinity Test, July 16, 1945 - Eyewitness Accounts - Even 32 kilometers (20 miles) away, scientists felt the heat of the explosion on exposed skin. Declassified eyewitness accounts of the Trinity test by Luis Alvarez, Enrico Fermi, Philip Morrison, Robert Serber, Victor Weisskopf, and others.
Szilard Petition, July 17, 1945 - Leo Szilard, and 69 co-signers at the Manhattan Project “Metallurgical Laboratory” in Chicago, petitioned the President of the United States. The names and positions of the signers are included.
Szilard Petition, July 17, 1945 - Full-color Image - See Szilard’s petition. Though it contained no secret information, the petition was not declassified until 1957.
Truman Tells Stalin, July 24, 1945 - At the Potsdam Conference in defeated Germany, President Truman told Stalin only that the U.S. “had a new weapon of unusual destructive force.” What did Truman say, and what did Stalin understand? Seven eyewitness accounts.
Truman Diary, July 25, 1945 - President Truman told his diary that he had ordered the bomb dropped on a “purely military” target, so that “military objectives and soldiers and sailors are the target and not women and children.”
Official Bombing Order, July 25, 1945 - The bombing order issued to General Spaatz made no mention of targeting military objectives or sparing civilians. The cities themselves were the targets.
Bomb Production Schedule, July 30, 1945 - The Manhattan Project was designed to make far more than a few bombs. The production rate of 3 bombs per month in August was expected to rise to 5 bombs/month in November, and 7 bombs/month in December.
Groves-Oppenheimer transcript, August 6, 1945 - General Groves informed Robert Oppenheimer of the Hiroshima bombing. Transcript of telephone conversation.
Truman radio speech, August 9, 1945 (excerpt) - In his radio speech to the nation on August 9, President Truman called Hiroshima “a military base.” This is an audio file. Hear Truman say it. Or read the full text of that paragraph.
Truman Revokes Bombing Order, August 10, 1945 - Horrified by reports of the enormous casualties in Hiroshima and Nagasaki, Truman ordered the atomic bombing stopped.
Leo Szilard, Interview: “President Truman Did Not Understand” - A 1960 interview with Leo Szilard about the use of the bomb, reprinted by permission from U.S. News & World Report.
Cool Central Site of the Day — August 6, 1998
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Created May 29, 1995 Last modified January 25, 2018
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