“They took over the Kurile Islands and still own them today, so you can imagine what the story would be if they have taken more terrirtory.”
Keeping the Russians out of a defeated Japan is a different motive from ‘necessary for the defeat of Japan.’
“There was also another political angle in that the Democrats feared a major backlash (with good reason), if we suffered anywhere near those predicted casualties when the president had the means to end the war sooner by dropping the bombs.”
More American lives were lost at Okinawa than in all the other major battles in the pacific up to then - combined. The other bad thing is the casulty ratio. There were 80k American casulties to 120k Japanese troops. That is what shocked the American command at the time that despite outright superiority in troop counts, that the Japanese defenders were able to hang with the Americans.
That is incorrect. 100K American lives were lost in the Pacific campaign, only 12K of which were lost on Okinawa, and a plurality of the losses in the Okinawa campaign were of Navy personnel, whose dead exceeded that of the Marines and the Army taken individually. American deaths from Guadalcanal and Iwo Jima, added together, exceeded the Okinawa death toll. This excludes, of course, the 10K killed during the Battle of Bataan, when American forces were on the defensive.