Here's the opinion of the leader of the US military at the time Yes, later Leahy apparently said, "It is my opinion," not, "At the time we all believed" ["that

Here's the opinion of the leader of the US military at the time Yes, later Leahy apparently said, "It is my opinion," not, "At the time we all believed" ["that the Japanese were defeated and ready to surrender...."] I'm willing to believe that some, maybe including Leahy, thought the US had only to stand back and wait for the inevitable surrender, with no ratcheting up of force necessary. But, at the same time, somebody [not including the Fleet Admiral?] was also preparing for a full boots-on-the-ground invasion of the Japanese mainland, which (going by the US death tolls of previous island invasions) would have sent thousands of Americans to their deaths. Unless that invasion plan was entirely fake--something nobody is suggesting--there were obviously plenty of people at the top who thought that the Japanese might not be ready to surrender. Suddenly a middle option appeared between just waiting and hoping and sending thousands of Americans to their deaths: drop atomic bombs. Even though an atom bomb would actually kill fewer people than the firebombings, it would represent an even greater threat of what could happen if they didn't surrender immediately. Maybe the Japanese were about to surrender. Maybe they would keep fighting and Americans would keep dying. Maybe the atom bombs would convince them to surrender. Or maybe not. Maybe nothing short of a full invasion would be required. Maybe even that wouldn't be enough to end it quickly, and the dying would continue for a very long time. The Japanese in many places had gone on fighting until they were dead without ever surrendering. In that context, with no benefit of hindsight, to say that the bomb was not dropped to win the war but just to intimidate the USSR is nonsense.