What the film has done is revive the popular justification for the nuclear bombings of Hiroshima and Nagasaki, which is the following: That the nuclear attacks on those two cities obviated the need to invade Japan and, therefore, supposedly ended up saving many more lives than those killed in the nuclear attacks.

In other words, the justification has long been a sort of cost-benefit analysis. Let's assume that 300,000 people would die in an invasion, including U.S. troops. The estimated number of people killed at Hiroshima and Nagasaki was around 100,000. Therefore, the argument goes, on balance the nuclear attacks on those two cities was beneficial because it brought an early end to the war and, therefore, spared, say, 200,000 more deaths that would have occurred in an invasion.

There has long been a good response to this cost-benefit justification, however. That response was that an invasion of Japan would never have been necessary. That's because Japan was ready to surrender. All that Japanese officials needed was a guarantee that U.S. officials would not execute their emperor. 

Moreover, it is a virtual certainty that faced with the distinct possibility of a Soviet invasion and long-term occupation of their country, Japan would have quickly surrendered to the United States even without the emperor guarantee, in order to avoid having to live under decades of brutal communist rule, as Eastern Europeans and East Germans were forced to do. 

But there is, I believe, a much more powerful argument for why the nuclear bombings of Hiroshima and Nagasaki should go down as the most shameful war crime in our nation's history.