The diplomatic intercepts included, for example, those of neutral diplomats or attachés stationed in Japan. Critics highlighted a few nuggets from this trove in the 1978 releases, but with the complete release, we learned that there were only 3 or 4 messages suggesting the possibility of a compromise peace, while no fewer than 13 affirmed that Japan fully intended to fight to the bitter end. Another page in the critics' canon emphasized a squad of Japanese diplomats in Europe, from Sweden to the Vatican, who attempted to become peace entrepreneurs in their contacts with American officials. As the editors of the "Magic" Diplomatic Summary correctly made clear to American policymakers during the war, however, not a single one of these men (save one we will address shortly) possessed actual authority to act for the Japanese government.
An inner cabinet in Tokyo authorized Japan's only officially sanctioned diplomatic initiative. The Japanese dubbed this inner cabinet the Big Six because it comprised just six men: Prime Minister Kantaro Suzuki, Foreign Minister Shigenori Togo, Army Minister Korechika Anami, Navy Minister Mitsumasa Yonai, and the chiefs of staff of the Imperial Army (General Yoshijiro Umezu) and Imperial Navy (Admiral Soemu Toyoda). In complete secrecy, the Big Six agreed on an approach to the Soviet Union in June 1945. This was not to ask the Soviets to deliver a "We surrender" note; rather, it aimed to enlist the Soviets as mediators to negotiate an end to the war satisfactory to the Big Six--in other words, a peace on terms satisfactory to the dominant militarists. Their minimal goal was not confined to guaranteed retention of the Imperial Institution; they also insisted on preservation of the old militaristic order in Japan, the one in which they ruled.
There's much more here, well worth the time. Next is a post from Clive Davis (no, not the music executive) that includes links to the WS piece and a fantastic essay from 1988 by Paul Fussel, literary critic and WWII vet who wrote Wartime, an essential book about WWII. Fussell was badly wounded in Europe but was being prepped for the invasion of Japan, and points out one of the major problems with atomic bomb critics, addressing someone who called the bombings "terrorism":
[T]hose who deplore the dropping of the bomb absolutely turn out to be largely too young to have been killed if it hadn't been used. I don't want to be needlessly offensive, nor to insist that no person whose life was not saved by the A-bomb can come to a clear - by which I mean a complicated - understanding of the moral balance-sheet. But I note that in 1945 Michael Walzer, for all the emotional warmth of his current argument, was ten years old.
Finally, Mark Steyn lends his wit and wisdom to the argument:
The Japs fought a filthy war, but a mere six decades later and America, Britain and Japan sit side by side at G7 meetings, the US and Canada apologize unceasingly for the wartime internment of Japanese civilians, and an historically authentic vernacular expression such as "the Japs fought a filthy war" is now so distasteful that use of it inevitably attracts noisy complaints about offensively racist characterizations. The old militarist culture - of kamikaze fanatics and occupation regimes that routinely tortured and beheaded and even ate their prisoners - is dead as dead can be.
Would that have happened without Hiroshima and Nagasaki, or the earlier non-nuclear raids? In one night of "conventional" bombing - March 9th - 100,000 Japanese died in Tokyo. Taking a surrender from the enemy is one thing; ensuring that he's completely, totally, utterly beaten is another. A peace without Hiroshima and Nagasaki would have been a different kind of peace; the surrender would have been, in every sense, more "conditional:" Japanese militarism would not have been so thoroughly vanquished, nor so obviously responsible for the nation's humiliation and devastation, and therefore not so irredeemably consigned to history. A greater affection and respect for the old regime could well have persisted, and lingered to hobble the new modern, democratic Japan devised by the Americans.
And that's the best argument for the bombs: you must utterly crush an enemy like Japan was if you don't want to spend the rest of your life looking over your shoulder for his return. We could have spent time, money and American lives killing many more Japanese civilians than we did in Hiroshima and Nagasaki, or we could have dropped two horrible weapons that stopped the nightmare that was WWII. Truman and the men who delivered those weapons did the right thing by all of us, and those who deny that truth are either ignorant of history or unable to see the event in its real context, or both.