Why use the
most powerful weapon
in human history?
On August 2, 1939, just before the beginning of World War II, Albert Einstein wrote to President Franklin D. Roosevelt. Einstein and several other scientists told Roosevelt of efforts in Nazi Germany to purify uranium-235, which could be used to build an atomic bomb. It was shortly thereafter that the United States Government began the serious undertaking known then only as "The Manhattan Project."
President Harry S. Truman, warned by some of his advisers that any attempt to invade Japan would result in horrific American casualties, ordered that the new weapon be used to bring the war to a speedy end.
If the United States did not bomb Japan and attempted to invade instead, there would be many more casualties. A study done for Secretary of War Henry Stimson's staff by William Shockley estimated that conquering Japan would cost 1.7–4 million American casualties, including 400,000–800,000 fatalities, and five to ten million Japanese fatalities. Rather than continue losing American lives, Truman made the executive decision to use the atomic bomb.
President Harry S. Truman, warned by some of his advisers that any attempt to invade Japan would result in horrific American casualties, ordered that the new weapon be used to bring the war to a speedy end.
If the United States did not bomb Japan and attempted to invade instead, there would be many more casualties. A study done for Secretary of War Henry Stimson's staff by William Shockley estimated that conquering Japan would cost 1.7–4 million American casualties, including 400,000–800,000 fatalities, and five to ten million Japanese fatalities. Rather than continue losing American lives, Truman made the executive decision to use the atomic bomb.