> The Japanese had been trying to surrender for some time before the
> butcher Truman dropped the bombs -- which was only for the purpose of
> intimidating the Russians, since the Japs were already trying to surrender.
The Japanese were a mixed bag of factions. Tojo and gang were ready to fight to the bitter end. A minority faction of the war cabinet wanted an armistice, an end to fighting without withdrawal of Japanese forces from China. The actual precipitating event for the surrender was the Soviet land onslaught against Japanese forces in Manchuria.
However, the story that the Russians were winning, when the Japanese had cleaned their clock in 1905, would have reflected very badly on the leaders. The Japanese bosses knew that surrendering to the US would be a lot safer than surrendering to Stalin, based on three months of postwar experience in Europe. LeMay had already pounded the crap out of Japan with chemical explosives; the A bombs weren't even in the top ten as city killers. But they provided a convenient excuse for both the Japanese and American bosses, and as you note a very inconvenient situation for Stalin, the biggest perceived threat to both.
So, enough of the war cabinet shifted to the "accept unconditional surrender" position that it became a political possibility. That decision was not a gentle one; the surrender recording prepared by Hirohito caused an armed invasion of the Imperial Palace by a thousand of Tojo's fanatic army followers, and hundreds of deaths on both sides of the battle, until Hirohito's followers were able to smuggle the records out to enough radio stations to broadcast the Emperor's surrender speech. The Imperial Son-of-a-Bitch agreed to invade China, and agreed to the rape of Nanking, and agreed to the attack on Pearl Harbor, and all the other atrocities that inflamed the world. But he risked his life to end the war, which would have restarted if we had hanged him as many believed he deserved.
I wish there was some other more beneficient miracle that could have ended the war with unconditional surrender and a peaceful American occupation. But the "surrender" contemplated by the Japanese before the Soviet declaration was actually an armistice. Without the A-bomb or something like it there would have been a joint occupation, probably with Tokyo a divided city, following a bloody battle with tens of millions killed.
Probably including my father. When I was at Berkeley, I found the 20 quarto volumes of the invasion plan for Japan in the basement of one the libraries. Of course I did not read the whole thing, but I got a frightening feel for the life expectancy of a U.S. Army artillery sergeant in Operation Downfall.
If there had been an armistice, the Japanese would have completed their nuclear weapons development about the same time Stalin did, resulting in a three-way nuclear exchange in the 50s or 60s.
I wish there was some other reason to develop spacefaring rockets without the H-bombs that justified them. Indeed, I wish Americans weren't so damned clever that we built cheap hundred kilogram H-bombs, compared to the Soviet multi-ton monsters that required them to build their gigantic boosters, admirably suited to orbiting Sputnik and later Gagarin. History is full of what-ifs.
Sometimes the what-ifs worked out just great, like the Berlin airlift. We showed the world that our air force could feed and even rebuild a giant city from the air, while Hitler's Luftwaffe couldn't feed Paulus's army in Stalingrad. That demarcated the end of Soviet expansion in Europe. The European forward-deployed nuclear missiles years later was another what-if with negative results, erasing much of the ideological gains of the airlift.
At the end of things, most of politics is showy demonstrations, with justification only tenuously tied to message and means. A really stupid, expensive, and bloody way to run a planet.
That is why I would rather work on technical architectures that bypass the whole nasty mess, and gather enough clever people to out-think the rat bastards. But predicting the behavior of glad-handing sociopaths is challenging. Most of my libertarian friends seem content to watch and react and judge afterwards when nothing can be done, rather than anticipate and forestall. Designing the future is lonely work, and sometimes the allies you must make are not as decent as the allies you would like to have.