So are you saying that using atomic bombs WAS immoral?
Theres no sound moral principle anywhere that justifies the targeting of civilian populations in combat. That has nothing to do with the two atomic bombs themselves, either. As another poster pointed out on this thread, the U.S. had already crossed the Rubicon on that question long before August of 1945.
(At least it was before the United States did it.)
But I don't think we can have a balanced discussion on the subject because we're simply too close in time to the event; there are those living who know people who were physically and mentally immersed in the war effort.
As long as someone is going to be able to believe, "If there wasn't a bomb then my father wouldn't have met my mother at the USO where she gave him a box of Twinkies and danced with him", then the discussion becomes more emotional than rational.