Hiroshima atomic bombing

The Hiroshima atomic bombing was the first use of an atomic weapon in war. For Harry S. Truman, it joined a secret wartime project to the urgent question of how to secure Japan’s surrender; for the public, it arrived first as news of a successful weapon and a promise that the war might soon end. The scale of the devastation was not yet known when Truman announced the attack. As reports accumulated, the event’s meaning widened from a military success to a reckoning with mass civilian death, radioactive harm, and the future danger of atomic weapons.

Secrecy and the decision to use the bomb

The project behind the weapon had been hidden even from many of the government officials whose work touched its enormous expenditures. On June 17, 1943, Truman telephoned Secretary of War Henry L. Stimson after investigators found unexplained spending connected to the Manhattan Project. Stimson told him that only a handful of people knew the matter personally and described it as a highly important secret development. Truman accepted Stimson’s assurance that the expenditure served a specific and worthwhile purpose. By July, further information had given Truman enough knowledge to understand the project’s essential nature. The later decision to use the bomb therefore concerned a secret whose existence and broad purpose he had learned well before he became President.

As the weapon neared completion, the central question among the advisers described in the account was how to end the war, not whether Japan should be made to surrender. Stimson and General George C. Marshall focused on ending the slaughter as quickly as possible. Stimson had directed that the bomb be produced at the earliest possible date to bring the war to a conclusion. He also warned Truman that he did not want the United States to exceed the atrocities associated with Adolf Hitler. Yet concern about conventional bombing raised a different problem: if Japanese targets were already devastated, there might be no fair background against which to demonstrate the new weapon’s power.

A harmless technical demonstration had been considered and rejected by the committee and its scientific panel. Marshall had at first contemplated using the weapon against a military objective, such as a major naval installation, and then, if necessary, against industrial centers after warning civilians to leave. By the time of the deliberations described in the book, however, Marshall apparently no longer favored that course. The scientists could not identify a demonstration likely to produce the overwhelming shock they believed necessary to induce surrender. Only one bomb might be ready, it might fail, and advance notice of a weapon that did not work could strengthen Japan’s resolve. Writing for the panel, J. Robert Oppenheimer reported that its members were not unanimous, but that they could propose no suitable demonstration and saw no acceptable alternative to direct military use.

The responsibility for advising the President rested with Stimson, but the ultimate judgment was Truman’s. He later recalled a consensus among James F. Byrnes, Stimson, William D. Leahy, Marshall, and other senior advisers that the bomb should be used, with Marshall emphasizing lives that an invasion could cost. Truman wrote that Marshall estimated an invasion of the Tokyo plain and other parts of Japan would cause at least a quarter of a million American casualties. He also said that he reached his own conclusion after long and careful thought and that he did not like the weapon. The account cautions that there may have been no single decisive instant when he made up his mind. Japan’s defeat was not, in this reasoning, the same as its surrender: continued resistance meant continued deaths, while the projected cost of invasion was considered avoidable if a shock could force surrender.

The news aboard ship

Shortly before noon on August 6, Truman and Byrnes left their usual company to have lunch with enlisted men in the after mess. Truman was seated with six servicemen and just beginning his meal when Captain Graham, a Map Room officer, brought him a map of Japan and a decoded message from Stimson. Hiroshima had been bombed four hours earlier. The report described the result as clear and successful, with effects greater than those of any previous test; a red pencil circle marked the city on the map.

Truman reacted with sudden excitement, grasped Graham’s hand, and told him to show the message to Byrnes. A second message soon arrived, placing the bombing at 7:15 the previous evening, Washington time, and again reporting success. Truman stood and called for the ship’s crew to listen. He announced that the United States had dropped a new bomb on Japan, described its power in relation to TNT, and called the operation an overwhelming success. The crew cheered. At the officers’ ward he repeated the announcement and said, “We won the gamble.” Merriman Smith observed that Truman was broadly smiling, though not laughing; in the first dispatch, he saw the prospect of a quick end to the war.

The ship’s radio soon carried news bulletins from Washington, followed by the President’s public message, released by the White House at 11:00 A.M. Washington time. It announced that an atomic bomb had been dropped and warned that the United States could destroy Japan’s capacity to make war through attacks on its productive facilities, docks, factories, and communications. The message threatened further destruction from the air if Japan did not accept the terms. At the time it was broadcast, Washington had no detailed account of the damage in Hiroshima. The announcement could therefore present the attack as a successful demonstration of power and a warning without yet conveying the human scale of its consequences.

The human cost comes into view

The early estimates were far below the eventual toll. J. Robert Oppenheimer had predicted perhaps 20,000 deaths. Reports from Guam on August 8 suggested that 60 percent of Hiroshima had been leveled and that deaths and injuries might reach 200,000. Later estimates placed deaths at about 80,000 instantly and another 50,000 to 60,000 in the following months; perhaps 10,000 of those killed were Japanese soldiers. Many more people suffered burns, shock, and radiation poisoning. The subsequent accounts cited in the book describe effects on civilians, including children, and establish a human cost that the initial reports aboard ship had not disclosed.

The distance between the first announcement and these later accounts matters. When Truman learned of the attack, the message in his hands reported success, not a verified death toll. The public statement likewise contained no figures for the damage because none were yet available in Washington. The initial response in the country was relief, especially among families with loved ones in the armed services, who hoped the war might soon be over. That relief preceded fuller knowledge of what had happened to the people in the circled city.

Reluctance, justification, and consequence

The account presents Truman’s reaction as more complicated than his exhilaration aboard ship alone might suggest. On August 9, he wrote to a correspondent who urged an uncompromising continuation of total war. Truman acknowledged Japan’s cruelty in warfare but said he could not accept imitating it. He regretted the necessity of destroying whole populations because of their leaders’ obstinacy and said he would not do so unless absolutely necessary. He described his aim as saving American lives while also expressing concern for Japanese women and children. That evening, in a radio address on the Potsdam meeting, he urged Japanese civilians to leave industrial cities immediately and save themselves.

These statements do not erase the decision to use the weapon or the mass civilian deaths that followed. They show the terms in which Truman understood his responsibility: the expected lives saved through a rapid surrender weighed against the destruction the weapon would cause. The bomb’s immediate success, as reported to him, and its actual human consequences were not the same kind of knowledge, and they did not arrive at the same moment. Hiroshima thus stands both as the culmination of a secret project and as the opening of a public encounter with atomic power—an encounter in which the promise of ending a war quickly was inseparable from the scale of civilian harm and the prospect that such weapons would be developed and used again.