I don't understand the debate of the meaning of ignore vs reject.
The US made ultimatum without a specific deadline. The hawkish press spoke in behalf of the government, but without authority. The US continued its plan to attack until surrender was communicated. No doubt powerful in US govt wanted to see what the bomb could do. Dropping two a-bombs in a week wasn't an accidental race condition against communication lines. The US leadership had two bombs and wanted to use them.
nobody expected them to surrender at the time, and they needed either to go trough a landings and ugly attrition war or display such force to let the parties surrender while saving face.
that's why the bombs and that's why the target were mid sized cities.
''We of the peace party were assisted by the atomic bomb in our endeavor to end the war,'' Koichi Kido, one of Emperor Hirohito's closest aides, said later.''
The targets were mid-sized cities because by the time the target planning started, Kyoto was the only big one the B-29s hadn't burned to the ground (well, the important parts; I forget when, but we'd given up on Tokyo after destroying 17 square miles or so), and Secretary of War Stimson, who'd visited it and Japan in general, removed it from the list, despite Groves imploring him many times to not. That was wise, if for no other reason that it strengthened the Emperor's hand when he was finally in a position to end the war, for a long time Kyoto was the Emperor's city, Tokyo the military's.
The US made ultimatum without a specific deadline. The hawkish press spoke in behalf of the government, but without authority. The US continued its plan to attack until surrender was communicated. No doubt powerful in US govt wanted to see what the bomb could do. Dropping two a-bombs in a week wasn't an accidental race condition against communication lines. The US leadership had two bombs and wanted to use them.