At the very least this saved the lives of millions of American soldiers, at the best it saved the world. I dislike the idea that people call Truman a mass murderer because of this, what he saw was a way to end the war quickly saving American soldiers.
Now I say it may have saved the world, I'm not talking about short term I'm talking long term. By using the bomb in actual war on actual people it gave people and more importantly governments a better idea of the destructive power of such a weapon. If the bombing of Japan did not take place and the power of the bomb was only displayed on tests maybe it would have been used in Korea, or the cold war. The knowledge of the costs of human life gave governments considerable hesitation before using it.
