Look up “Operation Downfall,” “Operation Olympic,” and “Operation Coronet.” These were the invasion plans for Japan.
American casualty estimates were staggering.
Americans were becoming war-weary. The carnage on Okinawa was a foretaste of what our troops would suffer on the mainland.
Yes, all these things were known before Hiroshima / Nagasaki.
I’m sure there were plenty of invasion plans drawn up. None of that means any of them were necessary, or even practical. Doesn’t the Pentagon have scenarios in place for an invasion of Canada?