"The Soviet Union had not participated in the Pacific campaign, choosing to remain neutral with Japan while fighting for survival against Germany. Truman was in Potsdam meeting with Churchill, trying to enlist the aide of Stalin, when he learned of the atomic test at Trinity."
At face value this is true, but this statement represents the totality of the Army's discussion of the Soviet role. The JROTC text minimizes the importance of the Soviets while elevating the significance of the atomic bombings in bringing about Japan's surrender. The Soviets are portrayed as being weak but it was Stalin's decision to enter the war and the Red Army's assault on Manchuria on August 9th and subsequent rapid advance through weak Japanese defenses that caused the Japanese to immediately sue for peace.
Truman and his trusted advisor, Secretary of State James Byrnes both believed the bomb would keep the Russians in line in Eastern Europe. Dropping the bomb launched the Cold War. It wasn't necessary to end World War II.
During the Tehran Conference in 1943 Stalin agreed that the Soviet Union would enter the war against Japan after Hitler was defeated. In 1945 at the Yalta Conference Stalin agreed to enter the War with Japan within three months of the end of the war in Europe. The Soviet invasion began on August 8, 1945, precisely three months after the German surrender on May 8th. The start of the invasion fell between the atomic bombings of Hiroshima, on August 6, and Nagasaki, on August 9. In the words of Air Force General Claire Chennault, "Russia's entry into the Japanese war was the decisive factor in speeding its end and would have been so even if no atomic bombs had been dropped." An examination of the Japanese historical record confirms this point. It is reprehensible for the Army to omit a more thorough discussion of the pivotal role of the Soviet Union in bringing about an end to the war.
"Truman was troubled by the mounting casualties in the Pacific as Allied forces drew nearer the Japanese home islands. Driven by the Bushido warrior code, the Japanese were prepared to resist to the last, and more willing to die than surrender."
Truman knew a week before Potsdam that Japan's emperor had intervened to attempt to end the war and there were several attempts at peace before this. Japan was prepared to surrender, provided that it could retain its emperor but Truman had two bombs and he was determined to use them to fire a kind of a shot across the bow to the Soviets as post-war Europe was taking shape. General Douglas MacArthur understood it this way. "The war might have ended weeks earlier, he said, if the United States had agreed, as it later did anyway, to the retention of the institution of the emperor.
Colonel Charles Bonesteel, Chief of the War Department Operations Division Policy poignantly described the situation in the summer of 1945, "The poor damn Japanese were putting feelers out by the ton so to speak -- through Russia."
"The Joint Chiefs told Truman to expect over 1,000,000 American casualties and even larger number of Japanese dead in the pending attack on the home islands."
This is false. There's no record of the Joint Chiefs of Staff formally studying the decision and they never made an official recommendation to the President, according to Alperovitz. Additionally, the Joint Chiefs never claimed to be involved. The claim of 1 million casualties as a result of an (unnecessary) American invasion is a complete fabrication. It originated from a 1947 Harper's article by Secretary of War Stimson. Stimson invented the number. It is not based on a shred of historical evidence.
For his part, President Truman randomly selected the number of American lives ostensibly saved as a result of dropping the bomb. He said it would "save thousands of American lives." He later remarked, "It occurred to me that a quarter of a million of the flower of our young manhood was worth a couple of Japanese cities, and I still think they were and are." He also said, "I thought 200,000 of our young men would be saved by making that decision."
The Japanese position was hopeless by the summer of 1945. They were trying to surrender because they were defeated. According to Brigadier Gen. Carter W. Clarke, "We brought them down to an abject surrender through the accelerated sinking of their merchant marine and hunger alone, and when we didn't need to do it, and we knew we didn't need to do it, and they knew that we knew we didn't need to do it, we used them as an experiment for two atomic bombs." Commanding General of the U.S. Army Air Forces, Henry H. "Hap" Arnold looked at the situation from the air, "The Japanese position was hopeless even before the first atomic bomb fell, because the Japanese had lost control of their own air."
"By August 1945, the United States had two nuclear bombs in its arsenal. On August 6, 1945, the Enola Gay dropped the first atomic bomb on Hiroshima. Over 140,000 Japanese were killed in the blast, and an uncounted number died from the lingering effects of radiation. On August 9, 1945, a second atomic bomb was dropped on the city of Nagasaki. The next day, August 10, 1945, Japan indicated its willingness to surrender."
Japan had been indicating its "willingness to surrender" for some time before the bombs were dropped. The Japanese finally acceded to allied surrender terms because the Soviets had invaded Manchuria the day before.
Every top American military leader was revolted by Truman's decision to drop the bomb. They couldn't see its military necessity. It is incomprehensible that the today's Army feels compelled to contradict its greatest leaders who understood the role of the military in relation to its political superiors. Commander of the U.S. Army Strategic Air Force, General Carl Spaatz understood the separation. He said, "The dropping of the atomic bomb was done by a military man under military orders. We're supposed to carry out orders and not question them. "That was purely a political decision. [It] wasn't a military decision.."
Top Naval officers joined in the chorus. Admiral William D. Leahy, the President's Chief of Staff said, "The use of this barbarous weapon at Hiroshima and Nagasaki was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender."