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During each operation, the Japanese continued fighting to the last man, thus inflicting enormous amounts of casualties against their American attackers. The bloody battles at Iwo Jima and Okinawa gave Truman and other leaders examples of what to expect during the invasion of the Japanese Home Islands. Following the fall of Okinawa, the official Japanese casualty count was 110,000 killed, and only 10,755 mostly wounded prisoners. The Americans suffered, 11,933 killed and another 39,119 wounded. American casualty counts, including the results from the large number of kamikaze attacks against the invasion fleet, only further solidified Japan’s determination to fight to the death. After three and a half years of war, Truman realized that the American public and congressional leaders would not accept those losses suffered at Iwo Jima and Okinawa and would demand answers. With the expected high casualty rate for the invasion of Japan, Truman’s decision to use the bomb instead of an invasion averted the need to waste the lives of thousands of American soldiers.1 The surrender of Germany on May 8, 1945 presented Truman and military leaders with pressures from the American people and Congress to demobilize millions of service members in Europe. In fact, 72 percent of Americans expected a partial redeployment and demobilization of European forces.
The idea was to discharge the soldiers with the longest time served in combat units and reassign all others to occupation duty or shipped to Pacific Theater bound units. Some of the point criteria included: length of service, overseas tours, battle campaigns, decorations, and number of Paul D. Walker, Truman’s Dilemma: Invasion or the Bomb, pp. 150 – 152.
David McCullough, Truman, p. 382.
Richard B. Frank, Downfall: The End of the Imperial Japanese Empire, pp. 122 – 124.
dependents. Once Germany surrendered, a large number of units destined for Japan rotated out a majority of their combat hardened officers and noncommissioned officers for less experienced leadership. Some divisions lost between 20 to 85 percent of their trained personnel. To get European units back to combat readiness, General Eisenhower estimated it would take at least six months. However, the army’s hard-pressed training plan allowed for only eight weeks of training that focused on combat against the Japanese. By the time the Japanese surrendered, several U.S Army units had even less training time to prepare for the invasion. An unnamed officer in the G-3 Section of the Army Ground Forces Headquarters stated, “The capitulation of Hirohito on 14 August saved our necks …. It would have been absolutely impossible for us to have sent well-trained teams to the Pacific for participation in the scheduled invasion of Japan.”4 While the American public expected a partial demobilization of forces after Germany’s surrender, a large portion of America believed that Emperor Hirohito was responsible for the war in the Pacific. This view was evident in a May 1945 poll that 33 percent favored the Emperor’s execution, 17 percent wanted him to stand trial, 11 percent wanted imprisonment, 9 percent believed in exile, and 11 percent saw him as a figurehead. Truman reaffirmed this feeling during his address to congress on June 1 that demanded the unconditional surrender of Japan, which received a standing ovation from Congress.5 Following the successful test of the atomic bomb, Truman now had another option that would save many American lives and shorten the war. An option he did not have at his meeting with the Chiefs of Staff on June 18, when he approved their plan for the invasion of Japan.
Truman still had the option to shelve the atomic bomb and go ahead with the invasion.
However, he was aware of the political and public consequences that decision would cause.
Ibid., pp. 124 – 126.
Ibid., p. 215.
First, the American people would demand explanations and accountability for the needless loss of life during the invasion of Japan, when it was avoidable with a secret weapon. Secondly, the military and administration would have to explain why the government spent two billion dollars of the taxpayer’s dollars on weapon research that had no application during the war. To aid in his ultimate concerns and decision, the availability of the atomic bomb provided Truman the only means that would end the war quickly with the least amount of American casualties. Like President Roosevelt, Truman never really considered or even received advice from his staff about not using the atomic bomb.6 Several of Truman’s advisors and scientists close to the atomic project believed that dropping the bomb on Japan would have a drastic impact on the international community following the war. However, Truman’s primary concern was not on how his decision was going to effect foreign relations before the Japanese surrender, but how to prevent more American casualties. In an interview with William Hillman and Morton Royce in 1955, Truman stated that, “as far as the bomb is concerned I ordered its use for a military reason – for no other cause – and it saved the lives of a great many of our soldiers. That is all I had in mind.”7 Several advisors close to Truman had mixed views about giving information about the bomb to the Soviets. Marshall wanted to know what the Soviets intentions were before providing them design information. While Byrnes believed the bomb would give the United States better advantage in international diplomacy, the United States would no longer need the Russian Army in Manchuria, and having this new weapon would keep the Soviets in line after the war. When Truman informed Stalin of this new weapon on July 24 following a session at the Robert J. Donovan, Conflict and Crisis: The Presidency of Harry S. Truman, 1945-1948, pp. 48 – 49.
Interview with former President Truman in 1955, n.d., in Truman Presidential Museum & Library, The Decision to Drop the Atomic Bomb: Truman and the Bomb, a Documentary History. Hillman was a newspaperman and Royce was a former professor from Georgetown University. Both were hired by Truman to assist in writing his memoirs.
Potsdam Conference, he believed that Stalin did not understand the significance. Only after the war did the United States learn that the Soviets had infiltrated the Manhattan Project early on and were constructing their own atomic weapon.8 Another instrument the United States had at its disposal, to assist Truman in his decision to use the atomic bomb, was in the intelligence field. Through a secret code-breaking effort called Magic for diplomatic traffic and Ultra for naval and military traffic, the U.S. intelligence community had the capability of intercepting and reading coded Japanese radio traffic from senior Japanese leaders in Tokyo to their units in the field and diplomats abroad. Even prior to Pearl Harbor, American intelligence agencies were busy trying to break the Japanese naval signals named JN25 by the Americans. These efforts did not produce significant results in deciphering the Imperial codes. Staying with the tradition of changing codes before major operations, the Japanese military changed its codes, which the U.S. named JH25b, just prior to their attack on the Pacific Fleet. This new code was impenetrable at first, but the United States would break the code in early 1942, prior to the Battle of Midway.9 The success American cryptologists had in breaking the Japanese codes was largely due to the over confidence and arrogance of Japanese leaders, who believed that their codes remained unbroken. The common practice for most nations was to use a certain code for a certain length of time and then replace it at random intervals. This practice would prevent their enemies from finding commonalities within the coded messages and breaking them. However, the Japanese expanded their territorial gains so quickly and covered a large part of the south Pacific that the distance between garrisons prevented the timely distribution of new codes. As the United States gained control of the sea and air in the Pacific, the Japanese efforts to supply their units with Herbert Feis, Japan Subdued: The Atomic Bomb and the End of the War in the Pacific, p. 89.
Ronald Lewin, The American Magic: Codes, Ciphers, and the Defeat of Japan, pp. 81 – 83.
updated codes became useless and then hopeless. The isolated Japanese garrisons continued use of their old codes gave the Americans the ability to break the most recent codes by comparing newer versions with the older ones. The inability of the Japanese to change their codes and their assumption that the codes remained unbreakable, allowed the Americans to ease drop on their military and diplomatic radio communications for the remainder of the war.10 The Magic intercepts provided the Allies with detailed information about the Japanese government’s view towards unconditional surrender and their attempts to keep the Soviets out of the war. To relieve American military pressure, the Japanese government tried to negotiate a peace settlement between Germany and the Soviets in late 1944. This would allow the Germans to concentrate their war efforts against the British and American forces. To counter the shift in forces, the Japanese believed that the Americans would divert forces and materials from the Pacific and reinforce Europe. During the course of a few months, the Allies intercepted fortyone messages between the Japanese Foreign Minister Shigemitsu in Tokyo and Ambassador Sato in Moscow which detailed their plans. However, Magic revealed that the Soviets were not interested in any negotiated peace settlement for the Germans. Later, the ability to read Japanese diplomatic traffic kept the Americans abreast on the Soviet’s intentions for the Far East. 11 Once the Soviets informed Tokyo that they would not renew the Non-Aggression Pact with them, intercepts provided the United States with details of how fruitless the Japanese attempts to get the Russians to renew the treaty or assist in mediating on behalf of Japan were.
Like previous attempts, the Soviets refused to accept the Japanese offers and stalled any attempts to meet with Stalin. The possibility of a Russian invasion into Manchuria grew as Japanese intelligence reports identified an increasing number of Soviet military trains heading east.
Ambassador Sato used these intelligence reports to assess his efforts to secure Soviet mediation and keep the Soviet Army out of the war. With the anticipated military build-up of Soviet forces completed by July or August, Sato reported to Tokyo on June 8, “that if Russia entered the war against Japan there would be no hope of saving the Emperor.”12
accepting the Allied demand of unconditional surrender. Even after advice from Japanese embassies and consulates, Foreign Minister Togo continued to insist that Japan would continue to fight on unless the Americans recognized “Japan’s honor and existence” and negotiated a more acceptable surrender that preserved the Emperor’s position. However, the military still maintained a controllable influence over the Supreme War Counsel, which split the decision makers on the issue of peace. With the Magic intercepts and the ferocity with which the Japanese military was fighting, the United States had no indication that the Japanese “armed services were ready to haul down the flag except on terms strictly honorable conditions.” Truman needed to decide which of the two options would end the war quicker with the least amount of American casualties. Executing the planned invasion or demonstrating to the Japanese that further resistance was suicidal by dropping the recently tested atomic bomb were his options.13 While Magic was busy deciphering radio traffic between Japanese diplomats, the United States was employing Ultra to intercept and listen in on the Japanese military communications.
Ultra revealed to the Americans that the Japanese military had no intentions of surrendering and preparations were underway to defend against an American invasion of Japan. A U.S.
intelligence report from April 1945 outlined that the Japanese were forming new combat units in
southern Kyushu and all defensive preparations concentrated on the projected U.S. landing sites.
The report further highlighted that all reinforcements went to the defense of Japan and the island garrisons were on their own. “Troops guarding the close approaches to Japan are dying in place in desperate delaying actions,” the report warned. However, the report grossly underestimated the Japanese troop strength on Kyushu. General Marshall briefed President Truman on June 18 that the Japanese had roughly 350,000 troops on Kyushu. The Japanese actually deployed 600,000 troops consisting of 14 divisions, seven mixed brigades and three tank brigades by late July.14 Ultra intercepts provided American decision-makers with every indication that the Japanese were preparing for a fight to the finish stance. More importantly, Ultra laid out in detail Japan’s defense strategy, order of battle, and their planned use for the dreaded kamikazes.