For those who believe that the Japanese were on the verge of surrender before the bombs were dropped, I suggest they read John Toland's "The Rising Sun." Togo and the militarists were willing to fight to the bitter end (much as Jefferson Davis was willing to do had he not been overruled by Lee, Johnson and Breckinridge). Millions of civilians were being trained to become suicide bombers.
How many Allied soldiers would have died? We don't know. Those who argue for relatively light casualties, it seems to me, assumed too much. I was an acquaintance of an officer who was on MacArthur's staff who had seen the estimates. He wouldn't disclose them but said they were substantial. (He also told me that he had, in fact, learned MacArthur's florid Victorian prose style to respond to letters, which ran counter to William Manchester's assertion that MacArthur responded to all letters personally. But that's another story.)
MacArthur's contention that the bombs were unnecessary should be considered in light of his hubris — no good idea could come from someone who wasn't Douglas MacArthur — and his bitter hatred of Truman, who had cashiered him in Korea. Mac, in fact, didn't much like any president, since he was obviously more gifted than they (despite his bungling of the defense of the Philippines). He disobeyed orders from Hoover and smashed the Bonus March camps in the Depression, and he hated FDR with a passion.
Eisenhower apparently offered no objection to the use of the bombs beforehand, and in his administration tactical commanders were allowed to decide whether to use nuclear weapons if they were out of contact with higher command. He also let loose his secretary of state to threaten repeated use of nuclear weapons.
Those who argued for an extended blockade of Japan ignore the fact that the Japanese civilian population would have suffered prolonged agony and death from a prolongation of the war. Starvation and disease aren't as dramatic as a mushroom cloud, perhaps, but they are lethal nonetheless.
This is not to say that the United States did not make horrific mistakes before, during and after the war. Toland contends that a semantic mistake scuttled pre-war negotiations. American policy toward Japan was rife with a mixture of romanticism (Chinese good, Japanese bad) and racism ("We're gonna have to slap the dirty little Jap" and the popular stereotype of Japanese solders as small, weak, buck-toothed and visually challenged).
Those who consider World War II the last "good war" should consider the horrific toll taken upon civilian populations. The bombing in Europe destroyed scores of German cities. The firebombing of Tokyo and other Japanese cities was as deadly, in fact, as the atomic bombs. Perhaps the escalation of violence made the decision to use the atomic bombs a natural step. Those who want to romanticize World War II should perhaps consider that the bombings of German and Japanese cities — as opposed to factories and other targets that specifically aided the war effort — would be considered war crimes today.
And it's an open question as to whether the United States would have, had the war in Europe continued, used the atomic bomb against Germany, i.e., white people. Maybe.
And there is a good question as to the morality of the decision to drop the bombs. I have often thought it was wrong, but I was not of the generation that had seen hundreds of thousands of its young men fall in a war to stop fascism from dominating the world; the Western democracies had many sins to account for, but can any of us say we would rather live under uncompromising fascism than under the messy democratic ideals we cherish?
I wish the bomb had not been used. I am ambivalent about its legacy. I will not overly criticize those who thought it necessary.