Note that Hiroshima and Nagasaki were not even the most brutal bombing runs on Japan that summer.
Two firebombing runs on Tokyo alone killed more people than the atomic bombs, and by the time of Hiroshima, almost every major city in Japan had been hit, some almost totally burned out.
The firebombing of Japan was so brutal that the Japanese supreme war council didn't even bother to convene until three days after Hiroshima - when the Soviet Union entered the war. Apart from being a new type of bomb, Hiroshima did not stand out as a substantial escalation.
