One thing that I find astounding is that Truman stated, and I quote: ""The world will note that the first atomic bomb was dropped on Hiroshima, a military base. That was because we wished in this first attack to avoid, insofar as possible, the killing of civilians."
A military base?

Pearl Harbor was a Military Base.
Hiroshima was a city. It contained military elements, but to state that it was a military BASE is absurd.
On other occasions Truman has stated that it was bombed because it was an industrial centre.
As per the US Strategic Bombing Survey, all the major factories were on the outskirts of the city. Next.
Oh, and he didn't realise what kind of victims they were going to be? Wrong!
And i quote: "The thought of wiping out another 100,000 people was too horrible," he said; he didn't like the idea of killing "all those kids."
(source: Barton J. Bernstein, "Understanding the Atomic Bomb and the Japanese Surrender: Missed Opportunities, Little-Known Near Disasters, and Modern Memory," Diplomatic History 19, no. 2 (Spring 1995): 257. General Carl Spaatz, commander of U.S. strategic bombing operations in the Pacific, was so shaken by the destruction at Hiroshima that he telephoned his superiors in Washington, proposing that the next bomb be dropped on a less populated area, so that it "would not be as devastating to the city and the people." His suggestion was rejected. Ronald Schaffer, Wings of Judgment: American Bombing in World War II (New York: Oxford University Press, 1985), pp. 147-48.)
Next, Hiroshima never figured in Bomber Command's list of the 33 Primary targets.
This is true also of Nagasaki.