While you are waiting for a discussion to develop, you might be interested in the FAQ entries at https://www.reddit.com/r/AskHistorians/wiki/faq/militaryhistory/wwii/usa#wiki_the_atomic_bombs.2C_aka_questions_.2Fu.2Frestricteddata_has_answered where /u/restricteddata and /u/t-o-k-u-m-e-i discuss the decision process.