I can't help but ask this question regarding the A-bomb thing: What would you propose to do different? How would you decision be better? Its easy to look back and say something was the wrong decision.
We don't have the same infomation they had back then. At the time, it was deemed the best solution for ending the war. If americans like killing millions and millions of people, then the would do it. They would have nuked all the nations trying to make nuclear bomb before they completed the task so they could be the supreme ruler of the world.