the war was long over before the A-bombs were dropped...if anything it was the napalming of most of the island months before the a-bombs were dropped that made the Japs finally awaken to the fact it was over as their war making capacity went down the crapper...people always talk about the A-bombs yet dismiss what napalming places like tokyo and other major cities really did to make the japs realize they could not end the war on their terms...
the a-bombs were just the whip cream on the horse sh!t- as the assertion the Russians entering the war forced the Japs hands is just ridiculous 1) the Russians got their revenge by taking japs in manchuria prisoner...2) the japs offered complete surrender right after the second bomb was dropped- not right after the russians entered the mix...
its sort of like these liberal dweebs who somehow want to give jimmah carter credit for negotiating a deal to free the hostages in iran who were sent home, oh yeh- one day after Reagan took office...
I don’t know of any first hand account in Amphibious Warfare Planning which believed an all out invasion upon the Mainland of Japan was a guaranteed success.
Statistically, the number of casualties for every significant amphibious assault against a fortified shore had doubled fro about the past 7 island campaign landings leading up to and including Okinawa.
1 million friendly casualties were conservative estimates from the Mainland Japan assault with provisos of steeper resistance since the enemy would have their backs against the wall and no other foreign invader had ever successfully assaulted the Mainland in her history.
Logistically, it appeared to be feasible, but also remember the American people had been at total war approaching 4 years and politically our resources also were beginning to dwindle.
There were many after Tarawa who questioned if amphibious warfare was a valid operational tactic.
IMHO, the Germany First policy later influenced by the Yalta then Potsdam Conferences did more to influence the Japanese position in the war. Without Germany, Japan didn’t have the resources to resist total war against the Axis Powers and the American use of Atomic power made the decision more intuitive.