To put an immediate end to the war
The USA was facing the prospect of invading Japan to subdue it. The last few battles, Iwo Jima and Okinawa particularly, were incomprehensibly bloody. Japan had no regard for its own citizens' lives and planned to turn their whole island into a fortress. It was estimated that casualties would be 1 million Americans and half a million British in the first invasion alone. Some cynics say we used it to scare Stalin as well, but the fact remains that they ignored an ultimatum on 27 July 1945 after enduring the worst conventional bombs could do. A powerful argument remains that the Bomb saved allied and Japanese lives.
The Allies demanded unconditional surrender of the Axis. In the Pacific Theater, the Allies, led by the United States, rolled up the Japanese expansion island by island. When Guam was taken, the Allies had a base from which stage an invasion. The estimates of American casualties for an invasion of mainland Japan was in excess of 1 million Americans. Possibly in excess of 2 million Americans. The United States dropped two atomic bombs to save American lives and speed the end of the war. Prior to using the atomic bomb, Japan was given ultimatums to surrender along with warnings of the dire consequences. The Japanese government ignored the warnings. While the use of the atomic bomb was a technological and strategic turning point in both WWII and all future diplomatic and strategic activities, there were more people killed, maimed, and injured during the Tokyo firebombing campaigns than by the atomic bomb.
To force Japan to surrender without further fighting. Japan surrendered very quickly thus saving the lives of over 100,000 American soldiers and perhaps as many as 1,000,000 Japanese who would have died if we had invaded Japan.
The Allies utilized atomic weapons to bring Japan to her knees. As an American, how hard would you fight an enemy if they were invading our nation? I mean literally on the soil of our 50 states? Then imagine how hard EVERY Japanese citizen, man, woman AND child, would be trying to kill OUR men, as we invade their nation.
Tensions were starting to build up in Europe between Soviet Union and its western allies. Since USSR had an overwhelming numerical superiority there, a show of force was needed to convince Stalin to "behave". Besides, the Russians were preparing for an invasion of Japan. I think these considerations were at least as valid back then as saving American lives.
According to some sources, Japan had a military force of over 9 million soldiers. Through battles like Midway, Okinawa, Iwo Jima, Guadacanal, and other "island-hopping" battles, 1.5 million soldiers either were killed or wounded enough so they couldn't fight. That meant that if Operation Olympic (the invasion of the main island of Japan) were to occur we would have to fight every soldier we had defeated before four times over! Even if we hadn't of dropped the atomic bomb, Hiroshima and Nagasaki would still have been targets for attack. This is because Hiroshima was a large industrial city that contained the 2nd Japanese Army Headquarters, which was in charge of all the defense systems in Southern Japan; Hiroshima also had communication centers for armies, storage points, and troop assemblies. Small industrial plants were also in the outskirts of the city. As for Nagasaki, it was the largest fully operational sea port in Southern Japan, which produced ships, equipment, and relief supplies. There is much other information that can be explained about the reality of dropping the bomb on Japan and this was one 'chunk' of information.
I agree with the guys who were talking about conserving American army resources and manpower. At Iwo Jima there were nearly 30,000 marines KIA. The Japanese lost nearly all of their army there. Imagine that in a place with cities, etc and bigger armies in a homeland .Even if you guys won, the Japanese would never forgive you. More deaths would have been caused than the bombs, and in more cities. The fact that a lot of Japanese fought to the death because they were never given a chance to surrender, and the fact that after Pearl harbor 13% of Americans said in a poll (13% of voting Americans, that is) that the only acceptable outcome of the war to them was the death of every Japanese man woman and child. Then there are slogans like, "kill japs, kill japs and kill more japs) and somebody said how the main language in Hell by the end would be Japanese. The Yanks were furious for Pearl Harbor and revenge is the most dangerous reason for fighting for both sides. The Japanese are brave people who see honor in death if the death is good (not in all death, though. Any fool can die in battle. True courage is living when it is right to live and dying when it is right to die). So, IMO, the A-bomb was used to reduce the expected casualty rate and loss of resources (tanks, weapons, etc all cost the taxpayers and government a lot of money) and I'm guessi
The objective was full and complete surrender. That's what they got from Germany, and that's what they wanted from Japan. The Japanese were fierce fighters with a strong sense of honor (in their opinion). This meant fighting to the death, no matter the odds. It was believed that they would continue to fight, even after it became apparent that there was no way for them to win. It was believed by Roosevelt that only a catastrophic event could stop the fighting. That catastrophic event was the H-bomb. When it wasn't immediately effective after Hiroshima, they dropped the bomb on Nagasaki.
You have a couple of really good answers already, but one point is missing.
Weapons are only good and marketable when tried out on real human targets.
The US government (or any government for that matter) has to justify the enormous development costs and ensure further production can be met by using the device.
As horrible as the result was feared, the return on the investment lead to further development of more powerful and expensive weapons in the US arsenal, all because 100,000 human beings died.
The cold hard bitter truth most history books and television stations don't talk about but entirely true.
As an Englishman I am not much use to you.I cant even compete with the splendid long answer. My understanding is they realised the Japanese people were going to defend their ancient homrland to the last man or woman (although it was them who started it in the first place) the Americans realised it would cost a million American service peoples lifes plus a vast number of Jananese deaths. The two bombs brought the war to a speedy close and although a great many japanese died it did still save a lot of lives overall.
The short answer...or at least the one the Gov't will give is that they wanted to save lives. Specifically the lives of GI's. The powers that be figured we would lose 1000's of US GI's if there were a ground invasion and occupation. So rather than invade, the US decided to play its Ace in the hole and release such power that Japan would have to surrender without it.
I need the information for a project I am doing and would appreciate an answer. Thanks.
