One does wonder about the SECOND bomb, of course.
As to the first bomb dropped?
I have no problems with that.
Had I known only what Truman knew at that time, I'd have ordered the mission, too.
I don't really wonder any more about the second bomb than I do the first. I'd be interested in why you do.
And also, I've read that some historians believe that not only would the alternative have cost thousands of American soldier's lives, but could have actually resulted in even more Japanese deaths than the bomb (assuming invasion was the alternative). An interesting topic for discussion for sure, but purely subjective and speculative. As for the OP's assertion that it was a war crime, total bullshit.
The projected loss in US lives alone to invade mainland Japan was estimated at a million.
Even if Eisenhower made the statement dickweed attributed to him, it's just proof of his ignorance in regard to the Japanese people. They would have died to the man protecting Hirohito.
The second bomb was dropped because Japan did not respond to a demand for surrender after the first one. They responded after the second one or there very well could have been more.
I may be wrong but I thought at that time there were only two bombs available. Am I mistaken? I have no source other than a memory of an old public tv educational prsentation.