The United States' decision to drop an atomic bomb on Hiroshima was more of a diplomatic measure calculated to intimidate the Soviet Union in the post-Second-World-War era rather than a strictly military measure designed to force Japan's unconditional surrender.
The United States Government's decision was influenced somewhat by popular sentiment of the war. Japan had an army of an estimated 5 million people. In his memoirs, Secretary of War, Henry L. Stimson wrote: "I was informed that such operations might be expected to cost over a million casualties, to American forces alone." A strategy was already devised to defeat Japan "without reliance upon the atomic bomb, which had not yet been tested in New Mexico." (Document A) From a report of a Scientific Panel, a moderate consensus was stated that "the opportunity of saving American lives by immediate military use, and believe that such use will improve the international prospects, in that they are more concerned with the prevention of war than with the elimination of this special weapon," helped bring support for the cause to use the bomb to end the war quickly. (Document G)
But the United States seemed not to be concerned so much with the defeat of the Japanese which as General H. H. Arnold, Commander of the American Army Air Force stated: "atomic bomb or no atomic bomb, the Japanese were already on the verge of collapse," (Document B), but instead with Soviet involvement in the war. The United States and Britain felt threatened by Russia. They knew that Russia was bitter from their loss of territory and dignity after Japan defeated them in 1904. At the Yalta Conference, Russia demanded its lost territory back. It sided against Japan on the condition that Outer Mongolia remain the same, and that what was taken from Russia in 1904 be given back to them. (Document D) Dwight D. Eisenhower recollected from a meeting with Harry S. Truman on the subject. "I told him that since reports indicated the imminence of Japan's collapse, I deprecated the Red Army's engaging in that war. I foresaw certain difficulties arising out of such participation and suggested that, at the very least, we ought not to put ourselves in the position of requesting or begging for Soviet aid. It was my personal opinion that no power on earth could keep the Red Army our of that war unless victory came before they could get in." (Document C) British Prime Minister expressed approval when finding out that the atomic bomb was dropped during the Potsdam Conference in July 1945. "We had no need to ask favors of them," he wrote. He then said to Mr. Eden, "It is quite clear that the United States do not at the present time desire Russian participation in the war against Japan." (Document E) Leo Szilard's recollection of a 1945 meeting between James Byrnes and a group of concerned atomic scientists sums up the US Government's feelings at the time. "The question of whether the bomb should be used in the war against Japan came up for discussion. Mr. Byrnes did not argue that it was necessary to use the bomb against the cities of Japan in order to win the war. He knew at that time, as the rest of the Government knew, that Japan was essentially defeated and that we could win the war in another six months. At that time Mr. Byrnes was much concerned about the spreading of Russian influence in EuropeÃ¢â‚¬Â¦ Mr. Byrnes' concern about Russia I fully shared, but his view that our possessing and demonstrating the bomb would make Russia more manageable in Europe I was not able to shareÃ¢â‚¬Â¦ I was dismayed when a few weeks later I learned that he was to be our Secretary of State." (Document F)
The United States Government's decision to drop the atomic bomb ultimately proved to scare Russia. As relations between the two countries weakened, the only way to receive respect from the other was to intimidate them. The war with Japan gave the United States a chance to off a power that only they had, thus making other countries subservient towards them.