The effects of the attack were devastating. The predicted Japanese surrender, which came on 15 August - just six days after the detonation over Nagasaki - ended World War II. Yet the shocking human effects soon led many to cast doubts upon the use of this weapon. The first western scientists, servicemen and journalists to arrive on the scene produced vivid and heartrending reports describing a charred landscape populated by hideously burnt people, coughing up and urinating blood and waiting to die.
As questions regarding the ethical implications of the attacks grew, the US Air Force and Navy both published reports which claimed (respectively) that the conventional bombing and submarine war against Japan would have soon forced her to surrender. Joseph Grew, America’s last ambassador to Japan before the war started, also publicly alleged that the Truman administration knew about (and ignored) Japanese attempts to open surrender negotiations with the US using the USSR as a mediator. At this time, another interpretation - most famously espoused in 1965 by political economist Gar Alperovitz in his book Atomic Diplomacy - emerged: the atomic bombing of Japan had been motivated by a desire to demonstrate the US’s military might to the Soviet Union, about whom the Americans were increasingly nervous.
The moral aspect of the attacks upon Hiroshima and Nagasaki continues to divide historians. While some argue that the terrible long term human cost to the Japanese population can never justify the use of such weapons, others maintain that in the context of total war, it would have been immoral if atomic weapons had not been used to end the war as quickly as possible.