A few days ago, Christine at iMinister blogged about Hiroshima Day. It's a good piece, and worth reading before returning here. It's okay, I'll give you a few minutes.
Okay, that's enough time.
The legacy of the first usages of atomic weaponry is an almost incomprehensible one. I mean, we'll understand that, but I'm not sure if it will take more time, more generations of removal, or if we're already past the point of most valid critical analysis. On the off-chance that this moment is it, I'm putting forth (again) my opinion.
The atomic bomb dropped against Hiroshima was a necessary thing. Not because of the lives of American soldiers/Japanese soldiers it would have saved - I've never trusted that rationalization; after all, it is the soldiers place to fight and die in war, so that the civilian may live. The bomb was dropped instead to herald in a new era of limited war. Pre-1945, casualties in war seemed to grow exponentially. Post-WWII, casualties per year from war remained at around 1 million, which seems rather high but become more impressive when you consider that ever-growing population of the world.
The atomic bomb was such a force that nations that had previously been willing to sacrifice hundreds of thousands were now faced with the possibility of a war that cost hundreds of millions, and suddenly, no major power wanted to risk that devastating. Certainly, powerful nations waged war, but one-sided wars, and not at any cost. Not a particularly good thing, but much better than the escalating cycles of devastation that had previously existed.
Of course, this limit on war, this destructive potential was shown with the first bomb. One real, (practical?) application was enough. The second bomb, the bomb on Nagasaki, was Truman being arrogant and impatient. It hardly can be justified as "We needed to make sure it worked the same every time" , and there is no further, more valid reason necessary for it's use. Hiroshima Day is a grim reminder of the cost of an era of limited war. Nagasaki Day is a testament to the risk the existence this weapon contains, and perhaps its greatest potential for abuse.