This is the 75th anniversary of the atomic bombing of Nagasaki. Three days ago was the anniversary of Hiroshima. I have two unpopular opinions about the bombings, one ethical and the other historical.
My ethical opinion is that the atomic bombings were not ethically (or morally) worse than the firebombings of civilians in cities all across Japan. More people died from the firebombing of Tokyo than in either Hiroshima or Nagasaki; it remains the most destructive bombing raid in history. Treating atomic bombing as where we cross the line means intentional conventional bombing of civilians is acceptable. It isn't. (And, no, it doesn't cause citizens to rise up and demand that their country surrender.) It's worth noting that the only reason Hiroshima had not been subject to conventional bombing is because it was reserved for the atomic bomb. Would it really have been less unethical to kill just as many people if only it had taken more bombs (more effort) to accomplish that?
My historical opinion is that the atomic bombs did not end the war. While controversial to the general public, it is largely accepted among scholars who've studied it, as best as I can tell. First, as noted above, strategic bombing of civilians does not end wars. Second, Japanese officials reported that they saw the atomic bombings as a continuation of the bombings that had already occurred. The War Council did not meet after the Hiroshima bombing. They did meet 75 years ago today and agree to surrender. They met in response to the Soviet invasion of Japanese-held Manchuria, and had not heard about the bombing of Nagasaki before the meeting. This timing, too long delayed after Hiroshima, before receiving word of Nagasaki, and in response to news of the Soviets declaring war on them, makes it wholly implausible that the bombs ended the war, despite 75 years of American nationalist myth-building.
Another note on the atomic bombings of Japan. There is a popular belief that the bombing was racist, that we would not have bombed the Germans, who were "white like us" (that is, our political and military leadership).
But the atomic bomb program was stimulated by Germany's world-leading prowess in physics and their taking of the Belgian Congo, with its known uranium deposits. The Manhattan Project was a race against the German atomic program (which may have been sabotaged by its chief, renowned physicist and 1932 Nobel Prize winner Werner Heisenberg), and the intent was to drop one on the Germans before they could drop one on Britain.
The many Jewish scientists in the Manhattan Project, including refugees from fascism, were relieved when Germany surrendered, thinking it meant the bomb would not need to be used. Their war was with Germany, which they were willing to nuke, not Japan, which they were not so willing to bomb.
For Truman, and some (not all) of his advisers, war was war, we were still in a war, and the bomb was just a tool of war. Had Japan surrendered earlier and Germany hung on into August, the bombs would have been dropped on German cities.