Truman was a political pick. I don't think Roosevelt had a two term VP.(Maybe John Nance Gardner--but i amto lazy to check).
The bomb may have been the first black project. Very seldom was Truman invited to the WH--it was a one man show,
It is to Trumans credit and Missouri background that he had the backbone to sit in the oval office as well as he did.
Awsome man to do that.
I do believe that he cowed folks with his presence--them thinking he was weak.
The militrary had proven their worth--prognosticating their efforts. Was onlt suspose th take 72 hours to conquer Iwo.
I think most all knew the military was up to their old bag of tricks. There were actually Generals and Admirals who wanted to fight every island on the way to Japan. Was not much better in Europe. Patto would have ended the war before Christmas and left the Russians licking their wounds---another general who wanted to inflict pain rather than win. Patton wanted to see the countrside before any body screwed it up.
I think that the body count would have exceeded 1,000,000 and that the war would have lasted another year----might have actually turned into another Viet Nam.
Blessings