At the end of his life nothing angered him more than people trying to say that decision was a mistake. I told him that these advocates weren't alive at the time and thus couldn't understand his point of view. They focus on what horrible destruction it caused and not the price Americans would pay if it had not been used. If there had been a ground invasion of Japan far more people would have died, both Japanese and Americans.
Also, Germany did something very similar near the end of the war, as they got desperate for manpower and fighting moved into their own territory.
[EDIT] Oh, and see farther down the page for, "Civilian losses, suicides, and atrocities". The lived experience of Okinawa (one of only a couple "home" territories for Japan that the US invaded before the bombs) was surely part of why so many expected an invasion of Japan to be a bitter, horrifying bloodbath.
At the time it probably did look like civilians were being turned into defensive soldiers- in the fullness of time, I think it looks more like a desperate and cruel army brutalizing a civilian population, sometimes pushing them into harm's way. I'd also presume that the treatment of the civilian population was worse for indigenous Okinawans-- maybe even today Okinawans can find themselves treated as 'not real Japanese'.
It's been a while since I read 'Embracing Defeat' but I recall its summary of the state of Japan towards the end of the war and a lecturer saying, in effect, that nobody had to invade Japan to cause the deaths of millions, the supply chain (Asian mainland colonies collapsing) / labor (men at all near military age gone to war and many of them dead or captured) / agricultural situation was so dire that the U.S. could have set a blockade and millions of Japanese would have died with 0 fighting.
The counter-argument to the necessity of the bombs is basically that the U.S. knew Japan could not effectively resist and though the U.S. might not have had a way of guessing, the highest levels of Japanese government were already in the process of discussing when and how to surrender right around the time the bombs were dropped. IIRC about the emperor's message of surrender, the bombs may have made it easier for the emperor to preserve face when surrendering, as such weapons make it easier to justify a surrender as a positive action.
That would be very prudish for Japan standarts in wwii.
The things they pulled in China and Indoshina would compete with the worst things that where made in the European Concentration camps.
Theo only reason they did not put Japan in a trial in the style of Nuremberg, was was the location of Japan, closer to the Soviet Union and later China.
If not for that, Emperor Hirohito and many of his followers would find themselfs in the end of a very short rope.
I can't alse even imagine the scale of bloodshed that an amphibian landing in the style of Normandy would cost in dead soldiers for a territory the size of japan.
It was also a great bluff for the Americans, because after they used where able to produce 4 bombs. They tested on in the desert, droped 2 in japan they got only one left after that they where saving to clean the beaches for a possible invasion.