Go take a look to Hell to Pay by D.M. Giangreco. Compared to the alternatives - mass starvation of the Japanese by blockade, or tens of millions of Japanese deaths, and one million American deaths, it's looks like a bargain, and it was viewed at the time as the last, best chance, to avoid invading japan.

The specter of nuclear war makes us wish we had never opened that Pandora box, but anyone making the decision in the past could not have made it any other way.