Hirohito was apparently convinced after the bomb on Hiroshima, the cabinet and military staff still wanted to fight on after the bomb on Nagasaki. They even tried to block his radio speech.
Personally, I think it was tragic, but there was not much choice. Forcing Japan to its knees by conventional means would have been a prolonged bloodbath (with the Soviets getting in the game as well), with probably a higher death toll.