Discuss the reasons for US use of atomic weapons against Japan.

In July 1939, more than two years before the US entered the Second World War, the Manhattan Project’s world-renowned scientist Albert Einstein urged US President Roosevelt to authorize a US Atomic research program. Roosevelt finally gave approval to begin and fund the program in October 1941.   Then, less than two years later on July 15, 1945 the US successfully tested an atomic weapon in New Mexico. The US now had a super weapon – a weapon of mass destruction.  On 25^th July, President Harry S Truman approved an order to use the atomic bomb whilst attending the wartime conference between the allies, US, Britain and the USSR at Potsdam in Germany.  On 6^th August a single US plane dropped an atomic bomb on the city and people of Hiroshima.  Three days later on 9^th August the US dropped a second atomic bomb on Nagasaki.  The reason given at the time for the use of atomic weapons was, as Truman stated in his August 6^th press release, that the bomb was used to ‘save American lives and bring the conflict to a swift conclusion’. However, this argument has been disputed both by contemporaries and by historians.

Historian Richard Overy argues that Truman’s assessment of military casualties for Operation Downfall  - the land invasion of Japan - as outlined in his public statement would have been catastrophic and dictated Truman’s action. However, Truman’s contemporaries like Admiral Leahy doubted the military necessity of using the weapon, as the Pacific theatre could have been won by maintaining the US naval blockade and conventional air bombings. The Soviets were also preparing to enter the war against Japan which would have forced an unconditional surrender. Historian P.M.S Blackett counters Overy’s view and suggests that Truman’s reason for using atomic weapons was not to end the war with Japan but to contain Soviet influence in the region. Blackett suggests that the decision to use atomic weapons was the first major action of the Cold War.

If we firstly consider the justification given at the time, and supported by Overy, the primary rationale for Truman’s decision was to avoid the high casualty figures predicted for a land invasion of Japan – Operation Downfall. During the Battle of Okinawa, between beginning of April and the end of June 1945, 12,500 US marines were killed, and nearly 1500 aircraft and crew were lost. This sent a powerful message to Washington. It was reported to Truman by his chiefs of staff  in late June that in the first phase of Operation Downfall the US would lose over 130,000 men. General Douglas MacArthur actually estimated over 50,000 casualties in the first 30 days. Truman’s War Secretary Henry Stimson was particularly worried by the potential scale of an invasion of the Japanese home islands.  Truman was dealing with projected figures of up to  1,000,000 casualties should a land invasion be necessary to defeat Japan. This statistic was reported and repeated in the US media, and this led to mounting public pressure on Truman to find an alternative to a land invasion to finally end the war. Therefore, there is clear evidence that Truman’s reason for using the atomic bombs was to save US lives.

In addition, Truman had acted on US intelligence reports which detailed that two million Japanese troops and hostile civilians were prepared to fight against an incoming invasion.  The US government knew that there were preparations to resist a US land invasion, civilians being trained as suicide bombers, and women and teenagers prepared to fight to the death.  The military members in the Japanese government believed that the bloodbath that would be created would undermine US resolve and enable them to force a negotiated settlement. Overy argues Truman’s decision was entirely based on the rationale that the new weapon could end Japanese resistance and force an unconditional surrender without the need to execute Operation Downfall.

Indeed, the reason the US used the atomic weapons was to convince the Japanese that further resistance was futile.  US intelligence reported that Japan was readying of 5,000 planes for suicide attacks. In March 1945 the Japanese halted supplies to ground forces abroad in order to focus solely building its homeland defences. By July, the two million Japanese ground troops were bolstered by seven tank brigades. Historian James Maddox views Truman’s decision as militarily motivated to provide the Japanese Emperor Hirohito with the justification he needed to move against the hardliners towards a surrender, which came on 15^th August 1945, 6 days after Nagasaki.

However, there is evidence to suggest that the atomic bomb was not necessary to end the Pacific War, as Japan was already defeated by July 1945. US incendiary air raids on Tokyo on November 1, 1944 had left 100,000+ dead. The majority of Japanese housing was compact (100,000 residents per square mile) and made of flammable wood. Incendiary bombing caused nearly 90% infrastructure destruction in 17 cities, and 99% destruction in Toyama. The US also had held a tight naval blockade and by March 1945, coal and iron imports had ceased. Oil imports ended in June, which meant aviation gas stock was in short supply.  This meant Japan could not sustain a defence from a full scale attack on its homeland and would have surrendered at the beginning of the launch of Downfall. With food imports cut off the Japanese were reduced to less than 1500 calories per day in 1945. Rations were limited to watered soup and black rice.  Thus, starvation and relentless air assaults had rendered the population weak and incapable of mustering a strong defence.  Civilian members of the Japanese cabinet were urging that terms be sought and agreed for surrender. Historian Paul Ham argues that US air and sea power had already pushed Japan on its knees, and that the decision to use atomic bomb was not militarily motivated.

Therefore, the reason for the use of atomic weapons, may have been, as historian PMS Blackett claims, not to avoid casualties or to shock the Japanese government to surrender but to contain Soviet influence in the region.  At the Yalta Conference in February 1945, cracks in the Grand Alliance were beginning to show as Stalin pushed for more and more concessions in Europe.  There was resistance from Britain’s Prime Minister, but Roosevelt generally sympathised with the Soviet claims that the USSR needed influence in Eastern Europe to ensure future security.   When Truman became president after the death of Roosevelt his administration then adopted a harder stance towards the USSR.  In April 1945, US war secretary Stimson stated that atomic weapons should be used to prevent communist expansion.  In addition, James Byrnes, US Secretary of State suggested to Truman in May 1945, that an A-bomb could be used to make the Soviet Union more manageable.  Truman and his administration therefore believed that atomic weapons could be used as a demonstration of US military power.   In their first meeting, just before the opening of the UN in San Francisco, in April 1945, Truman angrily accused Molotov and the USSR of breaking agreements made at Yalta. When delegates then met at Potsdam in July, Truman received news of the successful a-bomb test on 16 July 1945. The President’s delegation outlined to Stalin that the US had a new powerful weapon but, despite the fact the Soviets were their allies, they did not detail it as an atomic bomb.  Truman believed the Stalin had been able to gain too many concessions in Europe and was now alarmed at the potential impact of Soviet advances in China and the expansion of communist influence in Asia. Thus, there is evidence that it was the fear of communist expansion in the region that was the key basis of US decision making in July 1945. Significantly, by early August the USSR was in Manchuria.

Furthermore, the Japanese administration had been engaging in negotiations with the Soviets. Japan believed that if it worked through the USSR it could gain more favourable peace terms. This alarmed Truman.  Japan’s Premier Suzuki had approached the Soviets in May to request mediation in negotiations with the US. Historian Peter Kuznick argues that Truman decided to play a dual strategy to use the bomb to hasten Japanese surrender but this was done in order to reduce Soviet involvement and influence. It could be claimed that Truman’s real reason for his decision to use the atomic bombs was revealed two years later by his containment policy outlined in the Truman Doctrine of March 1947.  It was this premise, albeit not publicly stated, that was actually at play in August 1945.

To conclude, although historian Peter Kuznick holds Truman’s decision to use the atomic weapons in August 1945 was primarily motivated by his administration’s determination to contain Soviet expansion in Asia, this was not the key reason for the bombing of Hiroshima and Nagasaki. Indeed, the horrific casualty predictions for Operation Downfall, coupled with intelligence on Japan’s preparation for its homeland defence meant that Truman had no choice but to use the new weapons.  US tax payers had funded its development and in a total war it would be unfathomable for the president not to use a weapon that could save up to a million casualties.  Therefore, the reason that Truman authorized the first use of weapons of mass destruction was because he had the duty to save his own men and to bring a quick end to a long brutal war in the Pacific.