Yesterday (August 9) was the anniversary of the 1945 atomic bombing of Nagasaki, the second and hopefully final time nuclear weapons have ever been used in anger.
The American use of nuclear weapons remains one of the great historical controversies of the 20th Century. The orthodox position in the U.S., the traditional mixture of jingoism and selectively read evidence, is that the atomic bombings were necessary to bring the war to an end and saved tens of thousands of American (and Japanese, for that matter) lives. In 1945 my grandfather's tank battalion was in California practicing beach landings, and I don't think they were intending to invade Brazil. Because so many people in America can say that about their father or grandfather, this argument tends to be persuasive. Furthermore, there is little doubt that Operation Downfall would have produced horrendous casualties, a point which is usually enough to convince the casual historian of the Necessity of the atomic bombings.
Of course, if one has any but the most superficial understanding of the War it rapidly becomes apparent that this is a weak explanation. Conventional bombing, combined with the almost entirely successful Operation Starvation submarine blockade, could have accomplished the same thing. How many people realize that fewer people died at Nagasaki (80,000) or Hiroshima (~90,000) than in the largest conventional bombing raid on Tokyo (125,000)? By 1945 Japan had essentially no ability to defend itself from aerial attack. They could barely feed themselves let alone build and fuel planes, not to mention teach people to fly them effectively. So the "bombing to save lives" argument doesn't necessarily lead to nuclear weapons.
This leads us to the most prominent explanation among the cynical – the Scare the Russians argument. There is probably some truth to the claim that the military and political classes in the U.S. wanted to obtain Japanese surrender before the Soviets, who were rapidly charging across Siberia to invade Japan from the north, could reach the islands and thus stake a claim to post-War Japan. This probably would have led to West/East Germany or North/South Korea situation in Japan. This is a decent argument but it is incomplete.
Speed was a major concern, but the Soviet Union was only part of the problem. To understand the real need to end the War quickly, one must come to grips with the fact that Tom Brokaw and his Greatest Generation franchise are absolutely full of shit. Shocking, I know. This will be quite a leap for many of you to make, but close your eyes and imagine a world in which The Greatest Generation was basically the same as any other. The U.S. needed to end the War quickly because the public was rapidly getting sick of it. Truman and Co. needed to end it because the political will to fight for another year or two simply wasn't there.
A few historians – most notably Kenneth Rose (Myth and the Greatest Generation), Joseph Ellis, and Arthur Schlesinger Jr. – have tried but failed to pierce the powerful cloak of revisionist nostalgia that is draped over WWII in our collective memories, often suffering damage to their reputations in the process. But it the cultural myth of the America that was unanimously in support of Total War and making the attendant sacrifices simply wasn't there. Brokaw states:
The men and women who stayed behind were fully immersed in the war effort. They worked long shifts, rationed gasoline, and ate less meat. They rolled surgical dressings for the Red Cross and collected cigarettes for the boys 'over there' (p. 87)
That just isn't true. Not even close. Yes, many Americans fit this description (and everyone alive thereafter tried to claim that they were of this mindset during the War) but many did not. There was a rampant black market on which people obtained the rationed goods they supposedly sacrificed. Absenteeism from war work was beyond rampant. Millions dodged the draft in one way or another. Adultery, divorce rates, and juvenile delinquency (as the draft and women's entrance into the war workforce left millions of kids unsupervised) skyrocketed. The labor force ruthlessly exploited the dire need for military production to extract money for employers before abandoning those jobs for a new, better paying one. In short, even the small sacrifices that Americans were asked to make on the "Home Front" during the most important war of the last few centuries were too much for a lot of them to bear.
It stands to reason that many of the most "enthusiastic" or patriotic Americans signed up for service in one way or another, leaving war production work to those ineligible for service (women, the elderly, the very young, etc.) and the malingerers and opportunists. Those who were compelled by law or conscience to fight did so. Those who thought it might be more fun to stay safely at home making a killing in a labor-short market and banging the wives of servicemen who were overseas did so as well. That's the part that Brokaw and his followers prefer to forget while glorifying themselves – most of us are assholes, whether in 1945 or 2010. With WWII veterans dying at the staggering rate of about 1,000 per day it may not be long before we can take off the rose colored glasses and see the War to End All Wars in the cold light of reality. America resorted to a weapon of unprecedented danger in order to bring the War to a rapid conclusion, not only to save lives in an invasion and scare the Soviets but also in recognition of the political reality that the country was no longer willing to tolerate the most superficial sacrifices for much longer despite the vast economic incentives for doing so.