This is a fair criticism (although the generally accepted story is precisely that 'bombing people to smithereens' with atomic weapons led to surrender), but the

This is a fair criticism (although the generally accepted story is precisely that 'bombing people to smithereens' with atomic weapons led to surrender), but the evidence they based that opinion on is generally available. Having looked at it myself, I wouldn't have said everything they did with quite the same level of confidence, but I agree with their broad strokes opinion that it was most likely possible to achieve a Japanese surrender in a reasonable time-frame without dropping the atomic bombs or invading. My sense of it is that there was a strong feeling of the need to punish the Japanese, quite apart from any military necessity. I think that, combined with the need to demonstrate the power of the new weapons lead to a reluctance to seriously engage with the Japanese diplomatically. I take as evidence of that the fact that a key sticking point in the surrender decision was the status of the Emperor, who ultimately wasn't removed by the US anyway. The allies could have made their terms much clearer much earlier, and they could have engaged with the Japanese attempts to seek peace much more. And of course there was the ongoing worry that the Soviet Union might gain too much if things weren't sorted out quickly. From Truman's diaries at the time: > Discussed Manhattan (it is a success). Decided to tell Stalin about it. Stalin had told P.M. of telegram from Jap emperor asking for peace. Stalin also read his answer to me. It was satisfactory. Believe Japs will fold up before Russia comes in. I am sure they will when Manhattan appears over their homeland. I shall inform Stalin about it at an opportune time.