On the contrary, the Americans were anxious to secure Stalin's agreement to join the war against Japan, clear back to the previous great power conference.
And Russia declared war after the first bomb because that is when they were ready to attack and in fact attacked, so it was when the Japanese learned of it. But the allies knew of it long before that, they had already secured Russian agreement to enter the war against Japan before the first bomb was dropped. There was no issue of unity left to safeguard, and the point at issue - keep the emperor or not - was not one that divided the allies to begin with.
And no, the role of the unconditional surrender policy was not remotely symmetrical for Japan and for Germany. Germany was fighting a two front war and the allies entered it late, from the Russian's point of view. The unconditional declaration had helped avoid interallied fighting over the efforts each would make to defeat Germany. Germany (and its generals, including those seeking to overthrow Hitler) was continually dreaming of a split between the western allies and Russia to save Germany from final defeat. This was delusional, but there were serious post war tensions brewing between the Russians and the west in Europe. There was nothing comparable in the eastern theater, where everyone saw and knew that the US could finish off Japan without help if necessary and would occupy the place. Stalin wanted to get in at the end to grab territory on the mainland, while the US wanted to minimize its own casualties and welcomed the help.
Nothing to be gained by the unconditionality demand could go farther than active Russian participation in the war. The US had that in its pocket before it dropped the first bomb, and could use it along with its ultimatum, and could make that ultimatum less than unconditional easily. This was clear to all concerned and it is why it was directly advocated by high officials.
Ambassador Grew was acting sec state at the time but had been ambassador to Japan before the war. (Ambassadors retain that title regardless of later job, by the way, it is a rank like general in that respect). He knew their culture and what the emperor meant to their resistence. His advice was perfectly sensible.
Pointing out that others wanted the emperor removed is irrelevant because they lost that debate afterward, in the actual event. MacArthur kept the emperor. There was no US goal being secured by insisting on the ability to remove the emperor, because we didn't in fact remove him.
A peace reached without that unconditionality and also without the atomic bombings would have been less draconian, sure. There were no doubt any number of bloody minded men who would prefer the way it actually happened, regardless of whether the other course would have worked, out of hatred of the Japanese or out of a desire for prestige, or in the belief that really grinding their noses in it was the best way to wring any future resistence out of them. But if the ultimatum before the bomb had offered them a chance to keep the emperor and they had accepted, who the hell cares? It would have saved nearly half a million lives and still ended the war.
It is possible they would have rejected the ultimatum anyway. It is possible they would have rejected it, but caved after the first bomb and before the second. Nobody knows and it is beside the point. What isn't beside the point is the *moral requirement* to *seek peace* without *unnecessary loss of life*, if it can be had without sacrifice of the just political goals of the war. Grinding their noses in it isn't such a just goal, and removing the emperor wasn't one we actually sought. Killing more people just to avoid any need to offer it, was not morally justified.
Stimson and Grew saw this, Truman either did not or more likely didn't give a damn and wanted to look as tough as possible, for the sake of the Russians and for the sake of the electorate. But those are the vanity of the prince and not a legitimate right.
I think that the idea that the Reds would pin down the Japanese army in Manchuria and provide the US with logistical help (e.g., access to Soviet air bases) took form early on. Stalin promised Soviet entry into the war at Tehran (1943), and again at Yalta in February 1945.
So, if what you claimed earlier is true —
>>> >>> Once Russia agreed to attack Manchuria and actually did so, there was nothing whatever left to gain from it [unconditional surrender]. <<<
— then I don’t see either why there would be any necessity to keep with the idea after November 1943 (if what was needed was just an agreement for the Soviets to invade) or how you could say that the US stopped gaining from it in relation to Soviets “actually” invading since the Soviets started their invasion 3 days after Hiroshima was nuked.
Then again, as I stated earlier, the reasons for the (not-so-) “unconditional” policy with Japan were many and ever-changing.
The “unconditional surrender” policy wasn’t remotely symmetrical in the sense that for the Allies the “unconditional” for Germany was very strong, whereas it was “weaker” for Japan, whose “unconditional” surrender was actually given conditions early on. And Japan DID want to split the allies; they were just unable to do so (the Soviets ignored their diplomatic overtures).
What the US COULD do and what it WANTED to do were two different things that changed with the winds of war and diplomacy. Given the Soviet’s untrustworthiness as an ally — especially after Yalta — I don’t doubt that Truman would have been happy if Uncle Joe stayed out of the conflict if he didn’t feel the need to have him there to help reduce US casualties. A necessary evil, as it were. The A-bomb changed all that. In the end, many of the Soviet Union’s ambitions — a post-war Japan occupied by US and Soviet armies — were not realized thanks to our use of it. I gather that what Truman wanted was a prompt and relatively bloodless — in terms of American casualties — end to the Pacific War. That’s what he got with the use of the A-bombs at Hiroshima and Nagasaki. Ultimately, what Grew and Stimson wanted was irrelevant because — luckily for us, the Japanese and many others — Truman decided he didn’t want to wait... and wait... and wait for the Japanese to get off their duffs, stop killing people, and FINALLY surrender.
>>> A peace reached without that unconditionality and also without the atomic bombings would have been less draconian, sure... <<<
...And apparently was not a real possibility at the time —according to every military historian I’ve read who was not driven by a pacifist agenda or blinded by an anti-American or anti-Truman animus.
>>> What isn’t beside the point is the *moral requirement* to *seek peace* without *unnecessary loss of life*, if it can be had without sacrifice of the just political goals of the war. Grinding their noses in it isn’t such a just goal, and removing the emperor wasn’t one we actually sought. Killing more people just to avoid any need to offer it, was not morally justified. <<<
Truman was *seeking peace.* He got it — the war ended. What constitutes *unnecessary loss of life* was in large part the basis for his decision to use the A-bombs: Truman wanted to avoid the slaughterhouse that would have been Operation DOWNFALL. Many offers of peace had been made to the Japanese Imperial Gov’t — the Potsdam Declaration being the latest — and they were *rejected.* Your notion that the Japanese were suing for peace in the sping and summer of 1945 and that, if only we had guaranteed the personal safety of the Emperor, we would have had peace overnight is a fantasy unsupported by what I’ve seen on the historiography on the topic.
>>> But those are the vanity of the prince and not a legitimate right. <<<
It seems to me that you are less interested in understanding the end of the Pacific War, and the use of the A-bombs to achieve this, than in trying to besmirch Truman’s actions at the time.