text: It was very sad that many innocent victims died in the attacks on Hiroshima and Nagasaki but it prevented the U.S from having to invade the Japanese mainland at the cost of millions of Americans lives.  A survey was taken but the U.S government and they estimated that over a million U.S servicemen would be killed in the attacks on japans mainland.  Plus the countless number of Japanese civilian and Japanese military casualties that would be in result of an attack.  The attacks at Hiroshima and Nagasaki together only resulted in around 214,000 casualties.  In terms of life lost the invasion of the Japanese mainland would have been much worse than the attacks of Nagasaki and Hiroshima.  Also there is strong evidence that the Japanese had worked on atomic bombs themselves and they could have eventually used them on us.  Some of the people who have responded to this question are absolute idiots and are clearly misinformed of the events that took place in WW2.