“The Invasion of Okinawa is what made the atomic bombing of Japan inevitable.”
Yes, that’s the argument I’m familiar with the longest, that it in reality saved many more lives than if an invasion of the main islands of Japan had to be made.
It was the Okinawa that made American war-planners take notice. The fanaticism of Imperial Japanese troops was well-known. And taking Saipan was brutal. But Okinawa was something that blew their minds.