in short, yes it was needed to cause the end of the war. The goal was not to kill as many people as possible, it was to elimite infrastructure and dissable their ability to porduce more weapons.
Also for those of you who think that it was a war crime dont fully understand the situation at all. Firstly we had to respond to the attack at pearl harbor which was dastardly in and of itself. Secondly we had bombers that were droping leaflets for days, hundreds of thousands of them, tell the people to leave the town and evacuate the area. Not to mention we told the Japanese that they would face terrible destruction if they did not surrender, but how do you describe somthing that the world hasnt seen yet, so i dont think they understood what we were capable of. Lastly the germans were also in the process of building the atomic bomb as well, but if it werent for Niels Henrik David Bohr, the german jewish physisist who defected ot avoid being killed because he was jewish, came to america and finished the much needed mathmatical equations needed to make the bomb work. His counter part was NOT jewish and was still in germany working on the bomb for the germans, and did all that he could to slow it down and prevent them from having it.
It was just a miraculous series of events that lead to the US having it first, and it wasnt easy for the president to make that desision either, so to say he should have been tried for a war crime is rediculous. If the germans had control of it first, the world as we know it would be drastically different. And if the bomb wasnt used to end the war on BOTH fronts, then millions more lives would have been lost.
You people who dissagree are the kind of people who criticise hunters and could never kill an animal, but you run to mcdonalds and eat a hamburger without thinking twice... hypocracy and ingnorance at its finest.