"The scientists on the Target Committee also preferred Kyoto because it was home to many universities and they thought the people there would be able to understand that an atomic bomb was not just another weapon - that it was almost a turning point in human history"
What did they expect their own bomb to achieve? Didn't USA know the destructive qualities their creation had?
The quote you have printed there was spoken by me, so let me just elaborate on it a bit.
The scientists who made the atomic bomb and were at the higher levels of policy discussion (i.e. the ones who got to talk about targeting plans, who were all quite senior), were worried that the atomic bomb would be seen as "just another weapon" — that is, just an elaboration on conventional bombing.
Why did they worry about that? Because the "identity" of the atomic bomb — it's meaning — was not established. There were people who saw atomic bombing as just an elaboration on conventional bombing. The US had been burning Japanese cities by the dozen since March 1945 — the atomic bomb was not new in that respect.
One can even make an argument, and people today sometimes do, that the atomic bombs were morally and qualitatively the same as, say, the bombing of Tokyo. And while one can quibble with that (and I do), you can see the logic of it. The first atomic bomb could destroy a mid-sized city. So could conventional weapons.
So why were the scientists so worried? There were two reasons, the immediate and the long-term. Immediately, they hoped the atomic bombs would convince the Japanese to surrender. That required the Japanese to see the situation as having changed. So they needed to see the atomic bombs as something different from the firebombing — a real difference from the status quo.
The more long-term, though, is the more interesting, in my view. The scientists knew the atomic bombs they had were only the first draft. They had ideas on the table for doubling and quadrupling their firepower that they would implement before the end of the decade. They also understood that once you could put them onto long-range rockets, the whole geopolitical game was going to change. And they knew about the terrible possibility of what they called the "Super" — the hydrogen bomb — and it loomed heavily in their reasoning. The Super would be a nuclear weapon that was around 1,000 times more powerful than the bombs of World War II. It would set ablaze entire metro areas and spread radioactive contamination for thousands of miles. It was of a different character.
In 1946 or so the scientists calculated how many World War II atomic bombs they thought it would take to render the Earth too radioactive for human life. They thought it was on the order of 10,000-100,000 — a very large number. For the Super, they thought it might be on the order of 10-100. That's a very small number. Now, their calculations were very crude, and not correct as far as we know today. But it gives you an idea of what they were afraid of.
If the world thought the atomic bomb was a weapon that could be easily integrated into the military arsenals of the world — like a conventional bomb — then the world was sunk. Nations of the world would stockpile atomic bombs and this would, they thought, likely lead to world conflagration. To misunderstand the bomb was to misunderstand the terrible danger the world was in. They had modest confidence in their weapon; they did not have confidence in the global public.
After the war, the same scientists lobbied strongly for "international control" of nuclear weapons — that the UN or some other similar body would set up a system to guarantee that nobody produced nuclear weapons and nuclear war was impossible. They failed in this effort. But the choice of targets on Japan was done in part to support this kind of reasoning. Like many things in the nuclear age, there is a paradox at its core: the worse things are, the better they are. The more horrible the atomic bombings of Japan, the more likely nobody would use atomic bombs in anger again. And even though the scientists in question were wrong about international control, they were successful at that: Nagasaki was not just the second atomic bomb, it was the last atomic bombing. So far.
Hi there, there is always more to be said on this subject but you may be interested in some of these past answers from u/restricteddata, found in our FAQ: