Legend has it that Truman agonized over the decision to drop the bomb. This was not a decision made lightly. But in the end Truman realized that saving thousands of American lives was far more important than the number of Japanese civilian casualties. Truman had to put America first — something the current occupant of the White House won’t do.
Truman’s private papers and interviews showed no special agony beyond a natural aversion to regrettable tasks of any war.
“Truman had to put America first something the current occupant of the White House wont do.”
Neither would about 50% of the field of Republicans running for that office in 2016.
I think it went even deeper than that.IIRC the estimates were that a full scale invasion of Japan would cost a million lives...soldiers and civilians,Allies and Japanese.
The high death toll in the battle of Okinawa is what made his decision. I believe the only other battle in history where there was more loss of American lives was Gettysburg