Once you review Operation Downfall and what a land invasion of Japan meant...you really shake your head over the extended war (probably not ending until mid-1947).
The other curious thing which is never discussed....the Russians would have moved their land-troops to the east and probably started an invasion of their own upon Japan. The Russians were working on their own nuke, and who is to say that by the end of 1946...they had the opportunity to dump a nuke on Japan.