In terms of dropping the bomb, there were also various ideas for how it should be used against the Japanese. This included the argument that it could be used specifically for targeting a military objective such as a collection of factories and that the civilians around the target area should be warned before its use. Similarly, the idea was suggested that an outside demonstration be made to the Japanese so that they could witness the power of the weapon before suffering its use. However, neither Oppenheimer nor the military planners believed that a demonstration of the weapon would be sufficient to create a Japanese surrender. More so, they worried that any warning of the weapons usage would undermine the U.S. position if the weapon eventually failed to work.
Another significant factor that I believe is continually overlooked is the issue of Kyoto. Kyoto was the ancient capital of Japan which held a deep and powerful connection among the Japanese people. When the original bombing plans were developed by General Groves and other U.S. officials, they continually noted Kyoto as their preferred military target. Stimson, understanding the Japanese culture and the significance of such an attack, unilaterally ruled out Kyoto as a target stating that if it were bombed, the Japanese would fight to the last man and would never surrender. The significance of this is that although it is generally accepted that the bombings of Hiroshima and Nagasaki caused the Japanese surrender, if one of the targets had actually been Kyoto, then the event that marked the end of the war may have instead created a resurgence of Japanese will to fight.
The purpose of this paper is not to argue counterfactuals but is instead intended to highlight the complexities of the situation. It is clear that there were multiple reasons for using the atomic bomb, but that at the same time there were also alternatives which may have proved equally effective in prompting a Japanese surrender. One could argue that by just modifying unconditional surrender, the U.S. could have saved both U.S. lives and the lives of those Japanese residing in Hiroshima and Nagasaki. As noted  in the biography of Henry Stimson, “history might find that the United States, by its delay in stating its position [in regards to the Emperor] had prolonged the war.” Similarly, it can be argued that correlation does not equal causation and that as Hasegawa suggests, maybe the decisive factor was having the engagement of the Soviet Union, and not the dropping of the two bombs. Or, as Walker noted , it seems reasonable to conclude that “a combination of B-29 raids with conventional bombs, the blockade, the Soviet invasion, and perhaps a moderation of unconditional surrender policy would have ended the war without an invasion and without the use of atomic bombs.”
Regardless, Truman decided to use nuclear weapons on both Hiroshima and Nagasaki and days after the bombing of Nagasaki the Japanese did indeed surrender bringing an end to World War II.