@Aedes,
Aedes wrote:Hiroshima and Nagasaki had strategic military value -- that's not even questioned -- though by August 1945 the targets of greatest military strategic value had already been attacked, and to make the most dramatic demonstration of the bombs they did choose large urban targets rather than, say, a small military base. There is no evidence that they were targeted specifically to kill civilians, and they rejected targets like Kyoto that were of zero military value and extreme cultural importance.
I'm nitpicking in this post, rather than differing on matters of substance, but nitpicking can be important too.
Hiroshima was Japan's primary military port, held tens of thousands of Japanese soldiers, and held the military headquarters responsible for repelling any invasion in the southern half of Japan.
Nagasaki was an industrial center with almost its entire factory output devoted to supplying the Japanese military.
Hiroshima, at least, had to be among those targets with the greatest possible military value.
Kyoto was spared for its extreme cultural importance alone. It had factories devoted to weapons production too.
Aedes wrote:More people died in one night in Dresden than died in Hiroshima. So I'm not sure the "ease" of Hiroshima's destruction is in comparison to such overwhelming difficulty destroying cities by conventional means.
Dresden 25,000
Nagasaki 75,000
Tokyo 100,000
Hiroshima 130,000
Aedes wrote:But in retrospect we understand the radiation effects, the increasingly terrible magnitude of newer nuclear weapons, and the existential implications of nuclear armament, of which Hiroshima was the prelude.
We understood the radiation effects very well, before the A-bombs were even dropped.
People had been exposing themselves to horrendous levels of radiation via dime store X-ray machines throughout the 1910s and 1920s, and by the late 1920s the effects of this had become apparent. Hermann Joseph Muller presented a scientific paper in 1927 that detailed the dangers quite conclusively. The year after the A-bombs, he was awarded the Nobel Prize in Medicine for that 1927 paper.
Also, in the 1930s, Marie Curie died from radiation exposure. That was not an event that any of the A-bomb scientists were likely to have missed.