I got so tired of discussing this subject every summer when I lived in Japan. No matter how many times I tried to explain the various supportive viewpoints of most Americans, it nearly always fell on deaf ears.
One of the interesting things I ran into was that most Japanese did not take into consideration the very real possibility that not only did the bombings bring the war to a speedy conclusion to eliminate an Allied invasion of the main islands, it also prevented the Soviet Union from getting more land in Japan to the north. When I explained that the Soviets very probably would've taken Hokkaido and still occupy it like they do the Kurile Islands, a lot of people simply didn't want to hear it. When I said their territory could very well still be divided like the Korean peninsula, a few got the point, but most practiced selective hearing.
When I brought up the history of Japan's wars in Asia for the previous half century, including with the U.S. and what our forces experienced for 3.5 years fighting the Japanese in the Pacific, and why we didn't want to go through with a mainland invasion, this usually resulted in something like, "Well, why didn't they just drop a few bombs in uninhabited areas and then we would've surrendered anyway."
I don't believe this. Most of the people would've fought to the bitter end as ordered by their leaders, starving or not.
The atomic bombings shortened the war and ultimately saved lives on both sides.
I've been to the A-bomb dome and the Peace Museum. I've read a lot and thought a lot about the subject.
And the conclusion that I always come to is that Truman made the appropriate decision.
