The atomic bombings of Hiroshima and Nagasaki were some of the worst events in human history. That said, and may they never be repeated, one does have to understand the horrible choice President Truman had to make: Drop a couple of atomic bombs and kill/horribly injure hundreds of thousands (but have Japan surrender and end the war immediately) or have the US and allies invade Japan to end the war but at the costs of many millions of lives and the complete destruction of Japan (which would have been devastating for the surviving population).