Threads

The bomb

Trinity succeeded the day before the conference opened. What Truman knew, when Stalin was told, and how little the telling changed — Stalin already knew more than the Americans believed.

Day by day

The strongest passage on each day, with a link into the record at that exact point.

1. 17 July 1945The Big Three1st plenary · 4 passages

   After the ORSD formed the Manhattan Engineer District and based it in New York City (Manhattan) under the leadership of then U.S. Army Colonel Leslie Groves, it was on December 28, 1942 that President Roosevelt authorized the formation of the Manhattan Project. Its aim was now to put forward the research and science to craft a weapon out of the elemental forces of the universe at three different facilities across America, with the main facility being in New Mexico under the…

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2. 18 July 1945Dividing The Spoils2nd plenary · 2 passages

   The President showed the Prime Minister two telegrams that had arrived from Washington the night before confirming that the atomic bomb was essentially ready, even though Truman still had not received an exact description of the July 16th test. He told Churchill that he believed that Stalin should be informed, but was not exactly sure how to do it. Should the information come in the form of a letter, or through conversation? Churchill agreed that Stalin should be informed,…

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3. 20 July 1945Peace In Italy4th plenary · 1 passage

   With defeat at Japan’s doorstep and the atomic bomb essentially finished, different opinions among the allied leadership began to surface on how to end the war. Not only did Eisenhower show initial disapproval of the atomic bomb, but he also expressed his hope to Secretary of War Stimson that the United States would not be the first to deploy the most terrible weapon in the world. Some years later, though, Eisenhower would concede that his reaction was personal and based on…

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4. 21 July 1945The Polish Question5th plenary · 6 passages

   At 530, 16 July 1945, in a remote section of the Alamogordo Air Base, New Mexico, the first full scale test was made of the implosion type atomic fission bomb. For the first time in history there was a nuclear explosion. The test was successful beyond the most optimistic expectations of anyone. Based on the data which it has been possible to work up to date, I estimate the energy generated to be in excess of the equivalent of 15,000 to 20,000 tons of TNT.

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5. 24 July 1945The Nuclear Age Begins8th plenary · 9 passages

   President Truman had now been given the confirmation that the atomic bomb was waiting to be released.

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6. 25 July 1945Churchill Departs9th plenary · 7 passages

   Therefore, Truman was able to put added pressure on the Soviets that he otherwise would not have done had the bomb not been developed yet. However, aside from Truman appearing “tremendously pepped up” following Grove’s full description of the atomic bomb’s test on July 16th and then being more assertive at the fifth plenary session on July 21st, Truman neither said nor did anything of consequence to support this theory. Furthermore, the whole idea that the atomic bomb…

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7. 26 July 1945The Potsdam DeclarationRecess · 1 passage

   It was on this morning that the USS cruiser Indianapolis delivered an atomic bomb 10 feet long and 1 foot wide, weighing 9,700 pounds and filled with 141 pounds of Uranium-235.

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8. 27 July 1945The Price Of PeaceRecess · 2 passages

   “I would have been satisfied had the Russians determined not to enter the war. Notwithstanding Japan’s persistent refusal to surrender unconditionally, I believed the atomic bomb would be successful and would force the Japanese to accept surrender on our terms. I feared what would happen when the Red Army entered Manchuria.”

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9. 28 July 1945The New Big Three10th plenary · 1 passage

   There really was not much each delegation – including the Soviets – could say regarding Stalin’s comments. The United States was more than prepared by this point to force the Japanese to surrender with the atomic bomb and the Soviets needed the war to continue to expand their power and interests in the Far East afterward.

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10. 31 July 1945Settling The Polish Question11th plenary · 5 passages

    But the bombing campaign of World War II had changed so dramatically that the ethics of using an atomic bomb were not a priority for Truman at this stage in the war. As far as he was concerned, dropping it on Japan was not going to cross any moral lines that had not already been crossed. With the tens of thousands of civilians who became a target in the RAF and USAAF raids on Dresden in February 1945, coupled with the estimated 100,000 Japanese who were killed during the…

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