I know of no better argument than Paul Fussell’s article “Thank God for the Atom Bomb.”

http://www.uio.no/studier/emner/hf/iakh/HIS1300MET/v12/undervisningsmateriale/Fussel%20-%20thank%20god%20for%20the%20atom%20bomb.pdf

My Dad was on a destroyer at Okinawa. I remain deeply grateful that he didn’t have to be part of any fight to land troops on Kyushu or Honshu.