And the reason the USA dropped the bomb was to stop the USSR from invading Japan, and to stop the USSR at the 38th Parallel zone. Japanese cities had already been destroyed by conventional means (fire-bombing etc.) and the nukes were only a continuation of that. Japan's government realized they had more to fear from a Russian invasion than from the USA. By treaty with the Russians, the Kuril Islands were excluded from transfer to the USSR after WWII but the USSR took them by force anyway. By international law, the islands belong to Japan.
Truman dropped the bomb to avoid Operation Olympic and the projected 1 million US casualties by convincing the Japanese we would simply kill them like rats. And even then an attempted coup took place to try to stop broadcast of the Emperor's surrender announcement.
The Japanese would have fought for every inch of Japan with bamboo spears and explosives strapped to their backs if necessary.