This "solemn warning" was not transmitted through the usual neutral country diplomatic channels. It was merely broadcast by radio. Its solemnity may be gauged by the gratuitously insulting language. Furthermore, and what guaranteed its rejection, was that it stated a false intransigence on the part of the US. The sticking point for the Japanese was the retention of their emperor. In the actual peace treaty which the US ultimately signed, there were many concessions to Japan, including the retention of their emperor. But, on July 26th, as preparations for the live bomb demonstration went into their final phase, the last thing the US wanted was peace. The state of war with Japan was, in fact, a precious commodity. Because no amount of propaganda could have rationalized the dropping of an atomic bomb on a city in the absence of formal hostilities.
Note: Comments below in square brackets are my own.
At seven o'clock that evening, copies of the Proclamation were given to the press for release at 9:20 P.M.
…The time has come for Japan to decide whether she will continue to be controlled by those self-willed militaristic advisers whose unintelligent calculations have brought the Empire of Japan to the threshold of annihilation or whether she will follow the path of reason.
Following are our terms. We will not deviate from them. There are no alternatives. We shall brook no delay.
There must be eliminated for all time the authority and influence of those who have deceived and misled the people of Japan…
The proclamation specified that Japan would be occupied until its "war-making power is destroyed"; its sovereignty would be limited to its home islands "and such minor islands as we shall determine"; the Japanese military would be permitted to return home to lead "peaceful and productive lives." Japan was not to be "enslaved as a race or destroyed as a nation," but reconstructed along democratic lines. In conclusion, the Proclamation said, "we call upon the Government of Japan to proclaim now the unconditional surrender of all the Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction."
The document was signed by Truman, Churchill, and Chiang Kai-shek.
Stimson had advised the President that Stalin should also be asked to sign the Proclamation. If the Japanese pinned some final hope on Russia's neutrality, Stimson reasoned, then this hope should be closed off. When the Japanese realized that all the major powers were at last arrayed agains them, they would doubtless give up. Both General Marshall and former Secretary of State Cordell Hull agreed with this advice and urged Truman to obtain the additional Soviet "sanction" for the Proclamation. Before the Potsdam conference began, alternative phrases, including Russia as a signatory to the warning, were drafted for the Proclamation. Before the Proclamation was released, Truman had the optional phrases deleted. [My emphasis.]
Various advisers had suggested three different elements for the Proclamation, any one of which, their advocates felt, might be sufficient to occasion Japanese surrender: Stalin's signature, a guarantee to retain the emporer, specific mention of the atomic bomb as the source of the threatened destruction [My emphasis.] Not any one of these elements appeared in the Proclamation.
The Russians were not informed about the Proclamation until, immediately after it was released, [The newly appointed Secretary of State from South Carolina, James F.] Byrnes sent a copy over to [the Soviet Foreign Minister Vyacheslav] Molotov. Molotov's translator telephoned to inquire whether the Proclamation might be held up for two or three days.
On the next day, July 27, Molotov called on Byrnes.
The SECRETARY [Byrnes] said first of all he wished to tell Mr. Molotov that his request for a two or three day postponement in the issuance of the statement had only reached him this morning when it was too late.
MR. MOLOTOV replied that he had sent the word last night as soon as he had received the Secretary's letter.
The SECRETARY explained that even then it would have been too late since at 7:00 o'clock the statement had gone to the press for early morning release. He explained that the President for political reasons had considered it important to issue an immediate appeal to the Japanese to surrender. Two days ago he had discussed it with the Prime Minister [Winston Churchill] and he had received his consent to the issuance of the statement and had cabled Chiang Kai-Shek. On his return yesterday from Frankfurt the President had found a telegram from Chiang Kai-Shek agreeing to the issuance of the statement.
MR. MOLOTOV said that thus they had not been informed until after the release.
The SECRETARY said that we did not consult the Soviet Government since the latter was not at war with Japan and we did not wish to embarrass them.
MR. MOLOTOV replied that he was not authorized to discuss the matter further.
[Notice how Molotov catches Byrnes in the successive stages of his attempt to lie his way out of the embarrassment of not having consulted with the Soviets on the Proclamation. Byrnes' final escape route from his dilemma was to invoke the fact that the Soviet Union was not at war with Japan. This statement is heavily freighted with meaning which certainly would not have escaped Molotov and would have been relayed to Stalin. The deductions from it are:
The first of these signals the intention to resume a state of hostility between the US and the Soviet Union.
Taken together these two deductions lead to the following conclusion. With the successful test of the atomic bomb near Alamagordo, NM on July 16, 1945, the leadership of the United States believed it had a weapon in its hands so powerful that it could enforce its will on any nation on earth, but especially the Soviet Union.
There was only one problem. The awesome power of the new weapon was a secret and unknown to the very country that the US most wanted to impress. The leadership wanted a live demonstration. The window of opportunity for a live test opened on only one country, Japan, but this window would close at the instant of Japan's capitulation. And, as everyone knew, this was imminent.
This was Truman's problem in the three weeks between July 16 and August 6: To appear, for public consumption, to have made a sincere attempt to end the war while ensuring that the war continued until the bomb could be dropped. If he succeeded, he would have the weapon with which to terrorize the Soviet Union and the necessary elements to support the claim of the forthcoming US propaganda campaign that the Japanese brought it on themselves.]