But that brings us back to the other argument that the bombs were dropped to show Russia that the US had them, how powerful they were and that they were prepared to use them. It is an argument I can accept but primarily it was a way of ending the war, otherwise why drop the second. Clearly the fire bombing of Tokyo had no effect on the Emperor and government , the first A bomb didn't either so drastic measures were called for.It's interesting that you mention Dresden because it brings up an often overlooked part of the story.
The atomic bombs were not the most deadly attacks on Japan, it was the fire bombing of Tokyo, which killed 100,000 civilians in 1 night, wounded a further 125,000 and left 1 million homeless.
It is the single most destructive air raid in history hands down.
As for "needing" to drop the Atomic bombs to end the war, it doesn't really stand up to scrutiny. It's hard to believe a country that had seen 400,000 civilians burned to death with indiscriminate Napalm was going to have it's mind changed by the bombings of Nagasaki and Hiroshima which killed far fewer people.
The biggest reason for Japanese surrender was that Operation Starvation was so effective at causing famine in Japan that the US Government was providing hundreds of thousands of tons of wheat to Japan for 7 years post WW2 just to stop them all dying.
And the US military's own review of the war decided that the naval blockade would have ended the war on its own.
So the US didn't think the atomic bombs were necessary or the deliberate napalming of civilians.
I fully accept that my viewpoint is skewed because of my hatred for them (then not now)