This is a highly debatable subject. From the perspective I take the usage of the two Atomic bombs as a completely justified way to end one of the largest conflicts in recorded history. It was a nessecary evil to defeat a nation that would have fought to the last. Rather then burn through the Japanese countryside the usage of what some might consider overkill was the only way to end the conflict. By no means was it direct revenge for Pearl Harbor it was the end of the war.