Thank you, Dr. Oppenheimer

The bombings of Hiroshima and Nagasaki aren't depicted in the movie "Oppenheimer," but they haunt the film -- literally.

The eponymous physicist and "father of the atomic bomb," J. Robert Oppenheimer, is plagued by visions of the terrible destruction wrought by the weapon he helped create.

It's understandable that Oppenheimer would have qualms about the unfathomable horror inflicted on Hiroshima and Nagasaki, but launching these attacks was clearly the right decision.

Secretary of War Henry Stimson and President Harry S. Truman talked after the war of the cost estimates of an invasion of Japan going as high as 1 million U.S. casualties. These estimates are controversial but not unreasonable.

Certainly, there was every reason to expect ferocious Japanese resistance. At Iwo Jima, the Marines suffered an ungodly casualty ratio. Of 70,000 Marines committed to the battle, almost 7,000 were killed and another 20,000 wounded. Almost all of the roughly 20,000 Japanese soldiers on the island fought to the death.

In his authoritative account of the war's endgame in the Pacific, "Downfall," Richard Frank writes, "Given the record Japan had created, every American could foresee an unimaginably bloody finish fight requiring not only an invasion, but a further interminable struggle against Japanese armed forces elsewhere in Asia and the Pacific."

There can be no doubt that Truman's decision to drop the bomb saved American lives, whether it was 5,000, or 50,000, or 500,000. Since that was his first responsibility as the leader of the United States, this alone should create a strong presumption toward dropping the bombs being the right call.

The awful truth is that the atomic bombs weren't that different in kind from the incendiary raids already undertaken by Air Force Gen. Curtis LeMay. According to James M. Scott in his recent book, "Black Snow," LeMay's bombers burned down more than 178 square miles of 66 Japanese cities. Significant Japanese voices said after the war that the firebombing was an enormous and consequential blow to Japanese morale.

There's really no moral case against the atomic bombs that doesn't also apply to the firebombing. So if both of these tactics were to be left off the table, what would remain?

A blockade? In 1945, Japan was already looking down the barrel of mass starvation, with daily caloric intake constantly dwindling. The problem, obviously, with starving a country out is that a lot of people are going to die.

How about letting the Soviets do the dirty work? This would have had major geopolitical downsides, of course, and wasn't a particularly moral option, either, given that the Soviets killed roughly 350,000 Japanese nationals in their short time in the Pacific war.

It's also important not to forget the cost of the ongoing conflict throughout the region. Scott writes, "March 1945, for example, saw 240,000 noncombatants killed across Asia, an average of 8,000 people a day."

All the counterfactuals aside, the atomic bombs definitely ended the war -- and did it more quickly than any other option. The surrender message of the Japanese emperor spoke of a "new and most cruel bomb, the power of which to do damage is indeed incalculable, taking the toll of many innocent lives."

There is simply no way around the fact that defeating Imperial Japan, which brought bestial cruelty wherever it went, was going to require a cataclysm one way or the other -- whether from the air or the ground, whether a form of destruction very new or very old, whether sudden or drawn out.

"Oppenheimer" uses to great effect the famous, haunting line that the scientist is associated with from the Bhagavad Gita: "Now I am become Death, the destroyer of worlds." In the Pacific in the 1930s and 40s, it was Imperial Japan that was the destroyer of worlds. It had to be stopped. After years of struggle, Oppenheimer's handiwork finally did it and -- at a great cost, yes -- brought peace and amity where there had only been violence and despair.

Thank you, Dr. Oppenheimer.