I'm writing this a few days after the 60th anniversary of Hiroshima. Here are some numbers to think about. The larger numbers are estimates:
(Japanese) civilians killed by atomic bombs: 237,000
Japanese civilians killed by conventional bombs: 1,000,000
German civilians killed by conventional bombs: 1,000,000 - 3,000,000
Total deaths in World War 2: 55,000,000
There are two things that upset me about hand-wringing about Hiroshima.
1. It's hypocritical to angst about Hiroshima and not about Dresden or Tokyo.
2. It's hypocritical to angst about civilian deaths and not about soldiers.
The largest and the most intensive exterminations in history - in China, the Ukraine, Germany & Poland, Cambodia, Rwanda, the Dominican Republic, and Uganda, for instance - were conducted with knives, clubs, and guns, or enforced famine.
The great thing about the atomic bomb is that it enforces rationality on people by blowing away their naive optimism. Countries typically go to war because both sides get hyped up and believe they can beat the other side in a short time. Nuclear weapons are no more dangerous than sticks and stones. But people can't pretend that they can fight them off in heroic Hollywood style, winning thru their nation's superior courage and skill.