I think that asking who started the war is a moot point as from my understanding the war was probably unavoidable. You have to hungry nations extending the reach of their wealth and influence throughout the Pacific at some point these two would have had to come into conflict. I don't think either side would have yeilded to the other. There were many historical forces behind the dynamics off WWII, it makes my head spin trying to fit together all the diffrent angles.
As far as dropping the bombs. I do beleive that the US's 1,000,000 man bit did play a part in the decision, I know that it was much more than that. Dropping the bombs was a powerfull symbol of the US's emergance as a superpower. Also, as much as it was ment to show the US's power to our enemies I think it served an even more powerful role as declearation to our allies that we were incharge, that the US had become a shot caller, that Brittian and everyone else should know there place under the US.
Those are my thoughts the matter anyway whether it was justified or a war crime I don't know, but what I do know is that it is never right for a person to lose thier life.
I think the majority of credible historians, both western and eastern agree that Japan's Imperial ambitions were the main cause of the war. The militarists in japan at that time were trying to forge a greater Japanese empire which would span much of asia.
The Japanese military began an aggressive push (conquest) into China and Manchuria. The United States and Britian told them they must stop the military aggression or they would put an embargo on Japan's oil supplies -- which they did. Then the Japanese attacked at Pearl Harbor, killing 2,403 americans, and seriously damaging the American Pacific Fleet. The aggression in China and Manchuria, and the attack at pearl harbor, is pretty clear cut.
The dropping of the atomic bomb on Hiroshima and Nagasaki did put an end to the war. But some people feel that the Americans did not give the Japanese sufficient warnings of the power of the bomb so that the Japanese could have the opportunity to surrender without the devastation of the bomb. During the potsdam conference however shortly before the dropping of the bomb, Roosevelt made it clear to Japan that they must surrender or face ツ"total destructionツ". This had absolutely no effect on the Japanese militarists who were in power.
Some people have suggested that the bomb should have been dropped in an area where its power could have been displayed to the Japanese – They have suggested that America did not try hard enough to not drop the bomb on Hiroshima and Nagasaki. There may be some truth to this.
However, the fierce fighting on Okinawa, the Kamikaze attacks which destroyed around 400 american ships in a last ditch effort by the Japanese to stop the Americans from advancing toward Japan, showed that the Japanese militarists at that time were not inclined to surrender or give up easily at all. A land invasion of Japan, like the invasion on Okinawa, would have been extremely bloody, it would have cost millions of lives - both American and Japanese.
Nevertheless, I do wish that America had given a demonstration of the atomic bombs power to the Japanese and given the Japanese a chance to surrender. The pain, suffering and brutality that the war caused to millions of people on all sides of the conflict was a terrible thing. But to those who did not live through this very bloody War and want to condemn America I would say – the world was engaged in a titanic struggle at that time in history and America did display a generosity toward the countries it vanquished which japan and germany in that time in history would not have displayed toward America and other nations had they won the war. The war was about whether nazi germany, facist italy and imperial japan would create vast empires by carving up other countries. America decided, it was something worth fighting against and around 310,000 to 400,000 of America's best young men lost their lives in this conflict and around 670,000 were wounded.
To put things in perspective below is a causality list of world war 2. Taken from "world war 2 for dummies".
The Soviet Union lost the most with 25 million deaths, but only about a third were combat related.
China's death toll is incomplete but estimates are between 15 and 22 million.
Poland had 6 million deaths including 3 million Jews, roughly 20% of its prewar population.
Germany lost 4 million soldiers and 2 million civilians, many of them women.
Japan had 1.2 million battle deaths and another 1.4 million soldiers listed as missing, almost 1 million civilians were killed in the bombing raids between 1944 and 1945.
Over 1.7 million Yugoslavs and 500,000 Greeks died in the war.
France lost 200,000 soldiers and 400,000 civilians.
Italy lost 330,000 people.
Hungary lost 147,000 men in combat.
Bulgaria lost 19,000 in combat.
Romania lost 73,000 in combat.
Great Britain lost 264,000 soldiers and 60,000 civilians in bombing raids.
The United States lost 310,000 soldiers.
The Dutch lost 10,000 soldiers and 190,000 civilians.
Australia lost 23,000 men in combat.
Canada lost 37,000 soldiers.
India lost 24,000 men in battle.
New Zealand lost 10,000.
South Africa lost 6,000.
These totals do not include the 6 million Jews who perished in the Final Solution of Nazi Germany or the 17 million dead as a result of Japan's policies in Asia from 1931 to 1945.