“Invading Japan would have cost millions of lives.”
For one thing, this can only be justified using 20/20 hindsight.”
Not to a US military that just wrapped up the incomplete battle of Okinawa. We basically sealed off the northern half of the island and called it a win. It was a horrific battle on the first home island. We knew exactly what would happen invading the rest of Japan. Postwar intelligence confirmed they were right.
So you’re using an “incomplete battle” on a small island to reinforce your idea that invading the main island of Japan was ever a viable option? That makes no sense. If atomic bombs were not an option, do you really think the U.S. ever would have invaded Japan?