The Atomic Bomb: “The Year of Decisions”

Becoming a Detective:

On June 17th, 1945, President Truman writes in his personal diary, “I have to decide Japanese strategy – shall we invade Japan proper or shall we bomb and blockade? That is my hardest decision to date. But I’ll make it when I have all the facts.” To this day, many historians consider this “decision” as one of the most momentous of the 20th century.

Given the context of Truman’s recent ascension to the Presidency on April 12, 1945, and the fact that he had not been aware of the Manhattan Project prior to this time, would it have been realistic to expect him to stop the momentum underway or in fact offer an alternative Japanese strategy? In other words, did Truman decide to drop the bomb, or was the use of the atomic bomb inevitable?

Investigating the Evidence:

  • Document A: Excerpts from Truman’s diary from the Potsdam conference (Dated entries from July 17 to August 10, 1945)
  • Document B: Excerpt from document produced during June 6, 1945 meeting of Japanese Supreme War Council entitled The Fundamental Policy to be Followed Henceforth in the Conduct of the War.
  • Document C: Excerpt from diary of Secretary of War Henry Stimson regarding meeting of General Staff (Dated entry from June 11, 1945)
  • Document D: Memorandum by Manhattan Project scientist J. R. Oppenheimer, "Recommendations on the Immediate Use of Nuclear Weapons," (June 16, 1945)
  • Document E: General George C. Marshall(November 2, 1959)
  • Document F: Correspondence between Irv Kupcinet and Harry S. Truman, including draft copies of Truman’s letter, July 30 and August 5, 1963, responding to Mr. Kupcinet’s column in the Chicago Sun-Times about the dropping of the atomic bomb on Japan.
  • Document G: Excerpt from autobiography of Admiral William D. Leahy, I Was There (1979).
  • Document H: Richard G. Hewlett and Oscar E. Anderson, Jr., The New World: A History of the United States Atomic Energy Commission, Volume 1, 1939/1946 (1972).
  • Document I: Excerpt from David McCullough’s Truman, pages 400-401.

Searching for Clues:

Please answer the following questions in the formatted case log (PDF Format, Word Format) about each primary source document to help you understand their meaning.


Cracking the Case:

Based on your analysis of the documents and citing evidence to support you answer, please write a paragraph or two answering the following questions: Did Truman decide to drop the bomb, or was the use of the atomic bomb inevitable? Within your analysis, please indicate whether you were satisfied with the evidence and list any additional questions that have been left unanswered through your investigation.