FDR croaked on April 14, 1945, Truman was finally briefed about the Manhattan Project on April 24, 1945 and Postdam was in July 1945; so your "evidence" is crap. They did not magically develop nukes between April 1945 and July 1945.
You say I'm speculating about our willingness to nuke Germany, but it is a fact the the U.S. had over 100,000 people involved in various ways with the Manhattan project, we spent several years developing the bombs and spent 100's of millions of dollars - we were deadly serious. We didn't do all that as a theoretical exercise. You think we risked the lives of 100's of thousands of American troops to an invasion of Europe, but we wouldn't have ended the war with a single bomb if it had been available in time?
"Three, you say he inherited an ‘almost finished program’. This is not so. They hadn’t even tested the design of Little Boy before they dropped it. "
The biggest effort with the Manhattan Project went towards getting fissionable materials for the bombs - uranium 235 and plutonium. Without those materials you don't have a bomb, so until that infrastructure was in place to supply those materials, they couldn't test anything.
Potsdam July 17th, 1945.
Trinity, July 16th, 1945.
Just a coincidence, I’m sure. Truman wanted a test before Potsdam, that is why Trinity took place the day before.
“We didn’t do all that as a theoretical exercise.”
Not my argument, now is it? Again, there are good reasons why not to drop an atomic bomb on Germany that didn’t apply to Japan. Nuking your allies would be frowned upon. Most of the German industry is in areas close to the border.
“You think we risked the lives of 100’s of thousands of American troops to an invasion of Europe, but we wouldn’t have ended the war with a single bomb if it had been available in time?”
I’m saying that even if the bomb had been perfected by say 1943, that it’s unlikely that the situation in the Western war would have warranted it. By 1944, they had already committed to Overlord. So even if you shaved 2 years off the development (an already very tight and unlikely scenario) I still don’t see them dropping a bomb on Germany.