The United States Air Force dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki on the mornings of August 6 and August 9, 1945 during World War II. The goal was to secure the unconditional surrender of Japan. At least 120,000 people died immediately from the attacks, and many thousands more would die in years to come from the effects of nuclear radiation. About 95% of of the casualties were civilians. Japan sent notice of its unconditional surrender to the Allies on August 15, a week after the bombings. These bombings were the first and only nuclear attacks in world history.
The role of the bombings in Japan's surrender, as well as the effects and justification of them have been subject to much debate. In the U.S., the prevailing view is that the bombings ended the war sooner than would otherwise have been the case, and saved many lives that would have been lost on both sides if the planned invasion of Japan had taken place. In Japan, the general public tends to think that the bombings were needless as the preparation for the surrender was in progress.
Support for use of atomic bombs
Although supporters of the bombing concede that the civilian leadership in Japan was cautiously and discreetly sending out diplomatic communiques as far back as January of 1945, following the Allied invasion of Luzon in the Philippines, they point out that Japanese military officials were unanimously opposed to any negotiations before the use of the atomic bomb.
While some members of the civilian leadership did use covert diplomatic channels to begin negotiation for peace, on their own they could not negotiate surrender or even a cease-fire. Japan, as a Constitutional Monarchy, could only enter into a peace agreement with the unanimous support of the Japanese cabinet, and this cabinet was dominated by militarists from the Japanese Imperial Army and the Japanese Imperial Navy, all of whom were initially opposed to any peace deal. A political stalemate developed between the military and civilian leaders of Japan with the military increasingly determined to fight despite the costs and odds.
Historian Victor Davis Hanson points to the increased Japanese resistance, futile as it was in retrospect, as the war came to its inevitable conclusion. The Battle of Okinawa showed this determination to fight on at all costs. More than 120,000 Japanese and 18,000 American troops (72,000 casualties) were killed in the bloodiest battle of the Pacific theater, just 8 weeks before Japan's final surrender. In fact, more civilians died in the Battle of Okinawa than did in the initial blast of the atomic bombings. When the Soviet Union declared war on Japan on August 8, 1945 and carried out Operation August Storm, the Japanese Imperial Army ordered its ill-supplied and weakened forces in Manchuria to fight to the last man. Major General Masakazu Amanu, chief of the operations section at Japanese Imperial Headquarters, stated that he was absolutely convinced his defensive preparations, begun in early 1944, could repel any Allied invasion of the home islands with minimal losses. The Japanese would not give up easily because of their strong tradition of pride and honor — many followed the Samurai code and would fight until the very last man was dead.
After the realization that the destruction of Hiroshima was from a nuclear weapon, the civilian leadership gained more and more traction in its argument that Japan had to concede defeat and accept the terms of the Potsdam Declaration. Even after the destruction of Nagasaki, the Emperor himself needed to intervene to end a deadlock in the cabinet.
According to some Japanese historians, Japanese civilian leaders who favored surrender saw their salvation in the atomic bombing. The Japanese military was steadfastly refusing to give up, so the peace faction seized on the bombing as a new argument to force surrender. Koichi Kido, one of Emperor Hirohito's closest advisors, stated: "We of the peace party were assisted by the atomic bomb in our endeavor to end the war." Hisatsune Sakomizu, the chief Cabinet secretary in 1945, called the bombing "a golden opportunity given by heaven for Japan to end the war." According to these historians and others, the pro-peace civilian leadership was able to use the destruction of Hiroshima and Nagasaki to convince the military that no amount of courage, skill and fearless combat could help Japan against the power of atomic weapons. Akio Morita, founder of Sony and a Japanese Naval officer during the war, also concludes that it was the atomic bomb and not conventional bombings from B-29s that convinced the Japanese military to agree to peace.
Supporters of the bombing also point out that waiting for the Japanese to surrender was not a cost-free option—as a result of the war, noncombatants were dying throughout Asia at a rate of about 200,000 per month. The firebombing had killed well over 100,000 people in Japan, since February of 1945, directly and indirectly. That intensive conventional bombing would have continued prior to an invasion. The submarine blockade and the U.S. Army Air Force's mining operation, Operation Starvation, had effectively cut off Japan's imports. A complementary operation against Japan's railways was about to begin, isolating the cities of southern Honshu from the food grown elsewhere in the Home Islands. This, combined with the delay in relief supplies from the Allies, could have resulted in a far greater death toll in Japan, due to famine and malnutrition, than actually occurred in the attacks. "Immediately after the defeat, some estimated that 10 million people were likely to starve to death," noted historian Daikichi Irokawa. Meanwhile, in addition to the Soviet attacks, offensives were scheduled for September in southern China, and Malaysia.
The Americans anticipated losing many soldiers in the planned invasion of Japan, although the actual number of expected fatalities and wounded is subject to some debate and depends on the persistence and reliability of Japanese resistance and whether the Americans would have invaded only Kyushu in November 1945 or if a follow up landing near Tokyo, projected for March of 1946, would have been needed. Years after the war, Secretary of State James Byrnes claimed that 500,000 American lives would have been lost—and that number has since been repeated authoritatively, but in the summer of 1945, U.S. military planners projected 20,000–110,000 combat deaths from the initial November 1945 invasion, with about three to four times that number wounded. Many military advisors held that a worst-case scenario could involve up to 1,000,000 American casualties.
In addition to that, the atomic bomb hastened the end of the Second World War in Asia liberating hundreds of thousands of Western citizens, including about 200,000 Dutch and 400,000 Indonesians ("Romushas") from Japanese concentration camps. In addition, Japanese atrocities against millions of Chinese, such as the Nanking Massacre, were ended.
Supporters also point to an order given by the Japanese War Ministry on August 1, 1944. The order dealt with the disposal and execution of all Allied POWs, numbering over 100,000, if an invasion of the Japanese mainland took place. (It is also likely that, considering Japan's previous treatment of POWs, were the Allies to wait out Japan and starve it, the Japanese would have killed all Allied POWs and Chinese prisoners.)
In response to the argument that the large-scale killing of civilians was immoral and a war crime, supporters of the bombings have argued that the Japanese government waged total war, ordering many civilians (including women and children) to work in factories and military offices and to fight against any invading force. Father John A. Siemes, professor of modern philosophy at Tokyo's Catholic University, and an eyewitness to the atomic bomb attack on Hiroshima wrote:
"We have discussed among ourselves the ethics of the use of the bomb. Some consider it in the same category as poison gas and were against its use on a civil population. Others were of the view that in total war, as carried on in Japan, there was no difference between civilians and soldiers, and that the bomb itself was an effective force tending to end the bloodshed, warning Japan to surrender and thus to avoid total destruction. It seems logical to me that he who supports total war in principle cannot complain of war against civilians."
Some historians have claimed that U.S. planners also wanted to end the war quickly to minimize potential Soviet acquisition of Japanese-held territory.
Finally, supporters also point to Japanese plans, devised by their Unit 731 to launch Kamikaze planes laden with plague-infested fleas to infect the populace of San Diego, California. The target date was to be September 22, 1945, although it is unlikely that the Japanese government would have allowed so many resources to be diverted from defensive purposes.
Opposition to use of atomic bombs
The Manhattan Project had originally been conceived as a counter to Nazi Germany's atomic bomb program, and with the defeat of Germany, several scientists working on the project felt that the United States should not be the first to use such weapons. One of the prominent critics of the bombings was Albert Einstein. Leo Szilard, a scientist who played a major role in the development of the atomic bomb, argued: "If the Germans had dropped atomic bombs on cities instead of us, we would have defined the dropping of atomic bombs on cities as a war crime, and we would have sentenced the Germans who were guilty of this crime to death at Nuremberg and hanged them."
Their use has been called barbaric as several hundreds of thousands of civilians were killed, and the target areas were known to be heavily populated by civilians. In the days just before their use, many scientists (including American nuclear physicist Edward Teller) argued that the destructive power of the bomb could have been demonstrated without the taking of lives.
The use of atomic bombs, due to the effects of the particle radiation, may have made them poisonous weapons under international law in 1945, in which case their use would have been a war crime. Some have argued that Americans should have done more research into the effects of the bomb, including radiation sickness and the terrible burns that followed the explosion.
Some have claimed that the Japanese were already essentially defeated, and therefore use of the bombs was unnecessary. General Dwight D. Eisenhower so advised the Secretary of War, Henry L. Stimson, in July of 1945. The highest-ranking officer in the Pacific Theater, General Douglas MacArthur, was not consulted beforehand, but said afterward that he felt that there was no military justification for the bombings. The same opinion was expressed by Fleet Admiral William D. Leahy (the Chief of Staff to the President), General Carl Spaatz (commander of the U.S. Strategic Air Forces in the Pacific), and Brigadier General Carter Clarke (the military intelligence officer who prepared intercepted Japanese cables for U.S. officials); Major General Curtis LeMay; and Admiral Ernest King, U.S. Chief of Naval Operations, and Fleet Admiral Chester W. Nimitz, Commander in Chief of the Pacific Fleet.
Eisenhower wrote in his memoir The White House Years:
"In 1945 Secretary of War Stimson, visiting my headquarters in Germany, informed me that our government was preparing to drop an atomic bomb on Japan. I was one of those who felt that there were a number of cogent reasons to question the wisdom of such an act. During his recitation of the relevant facts, I had been conscious of a feeling of depression and so I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives."
The United States Strategic Bombing Survey, after interviewing hundreds of Japanese civilian and military leaders after Japan surrendered, reported:
"Based on a detailed investigation of all the facts, and supported by the testimony of the surviving Japanese leaders involved, it is the Survey's opinion that certainly prior to 31 December 1945, and in all probability prior to 1 November 1945, Japan would have surrendered even if the atomic bombs had not been dropped, even if Russia had not entered the war, and even if no invasion had been planned or contemplated."
However, it should be noted that the survey assumed that continued conventional attacks on Japan—with additional direct and indirect casualties—would be needed to force surrender by the November or December dates mentioned.
Others contend that Japan had been trying to surrender for at least two months, but the U.S. refused by insisting on an unconditional surrender. In fact, while several diplomats favored surrender, the leaders of the Japanese military were committed to fighting a "decisive battle" on Kyushu, hoping that they could negotiate better terms for an armistice afterward—all of which the Americans knew from reading decrypted Japanese communications. The Japanese government never did decide what terms, beyond preservation of an imperial system, they would have accepted to end the war; as late as August 9, the Supreme Council was still split, with the hardliners insisting Japan should demobilize its own forces, no war crimes trials, and no occupation. Only the direct intervention of the Emperor ended the dispute, and even after that a military coup was attempted to prevent the surrender.
Another criticism is that the U.S. should have waited a short time to gauge the effect of the Soviet Union's entry into the war. The U.S. knew, as Japan did not, that the Soviet Union would declare war on Japan three months after V-E Day, on August 8, 1945. The loss of any possibility that the Soviet Union would serve as a neutral mediator for a negotiated peace, coupled with the entry into combat of the Red Army (the largest active army in the world), might have been enough to convince the Japanese military of the need to accept the terms of the Potsdam Declaration (plus some provision for the emperor). Because no U.S. invasion was imminent, it is argued that the U.S. had nothing to lose by waiting several days to see whether the war could be ended without use of the atom bomb. As it happened, Japan's decision to surrender was made before the scale of the Soviet attack on Manchuria, Sakhalin Island, and the Kuril Islands was known, but had the war continued, the Soviets would have been able to invade Hokkaido well before the Allied invasion of Kyushu. Other Japanese sources have stated that the atomic bombings themselves were not the principal reason for capitulation. Instead, they contend, it was the swift and devastating Soviet victories on the mainland in the week following Stalin's August 8 declaration of war that forced the Japanese message of surrender on August 15, 1945.
Many critics believe that the U.S. had ulterior motives in dropping the bombs, including justifying the $2 billion investment in the Manhattan Project, testing the effects of nuclear weapons, exacting revenge for the attacks on Pearl Harbor, and demonstrating U.S. capabilities to the Soviet Union. Scientists who had worked on the project later noted that they were pressured to finish the bomb by a set schedule, one which was timed to coincide with the Russian entrance into the Pacific theater, and one which additionally implied that the war would be potentially over very soon.
After the Hiroshima bombing, President Truman announced, "If they do not now accept our terms, they may expect a rain of ruin from the air the likes of which has never been seen on this earth." On August 8, 1945, leaflets were dropped and warnings were given to Japan by Radio Saipan.