“The Japanese had passed their intentions to capitulate through their supposedly neutral intermediary, the Soviet Union. The Russians sat on this information long enough to declare war on Japan and help themselves to some major spoils.”
Something is wrong with this timeline. The Russians were at war with Japan at that time and were not neutral. It would make no sense for the Japanese to consider Russia as a neutral country between the dates of the Hiroshima and Nagasaki bombings, because Russia was already in combat with the Japanese army on the mainland. The overtures by Japan for ending the war were made through neutral countries like Sweden and Portugal, but were rejected by the US because there were always conditional terms attached. The US had made it very clear to all parties that only an unconditional surrender was acceptable.
August 8, 1945 - Soviet Union declares war on Japan.
August 9, 1945 - Nagasaki is nuked.
Prior to August 8, the Soviet Union was a neutral in the war taking place in the Pacific.
August 6: Bombing of Hiroshima shortly after 8 a.m.
August 9: At two minutes past midnight on August 9, Tokyo time, Soviet infantry, armor, and air forces had launched the Manchurian Strategic Offensive Operation. Four hours later, word reached Tokyo that the Soviet Union had declared war on Japan.
That four hours later would be approx. 4 a.m. Japan time. The bomb was dropped on Nagasaki about seven hours later, roughly a three hour delay because the primary target (Kokura) was fogged in, there was fog on the secondary target (Mitsubishi shipyards) in Nagasaki, but the tertiary target in Nagasaki (Mitsubishi steel works) was clear.
Suggest you rent the movie "Japan's Longest Day" (Japanese with English subtitling) if you want a very accurate historical account with secondary entertainment value. It does an excellent job of covering events from late July 1945 (when the U.S. first indicated what the Japanese viewed as flexibility on the Potsdam declaration, i.e. allowing the emperor to remain on the throne) until the emperor's surrender broadcast on August 15, 1945.
Most older Japanese (and many of my generation as well) are very much aware of the Soviet duplicity in this matter even if it was whitewashed by the American media because the Soviet Union were still our allies at the time.