In a postbellum environment, far more war crimes are ultimately left untouched than are ever pursued in tribunals. This is particularly true if the victors commit the crimes against the vanquished. If that victor is a superpower, the difficulties involved in the pursuit of justice increase exponentially. As World War II entered its final stages the belligerent powers committed one heinous act after another: the Japanese military massacred civilians in Manila and murdered allied prisoners of war and slave laborers in an attempt to hide the evidence of their barbaric treatment, not to mention the ongoing acts of brutality in China. On the victors' side, while the United States and Britain bombed German and Japanese cities and their civilian inhabitants into oblivion to “bring the war to a speedy end,” the Soviet Union was unleashing acts of vengeance on the German population. Fresh from victory over the Nazi regime and emboldened by favorable political developments in Eastern Europe, the Soviet Union turned its attention to Japan.
On August 8, 1945, after weeks of deflecting Japan's requests to mediate a surrender to the United States and its allies, Soviet Foreign Minister Molotov presented Japanese Ambassador Sato with a declaration of war, thereby breaching the Neutrality Pact that remained in force between the two countries. The declaration stated that, “the Soviet Government decided to accept the proposition of the Allies and joined the [Potsdam] declaration of the Allied Powers of July 26….” Soviet acceptance of the Potsdam Proclamation meant recognition of the content of the Cairo Declaration of December 1943, which stated that the Allies “covet no gain for themselves and have no thought of territorial expansion.” Two years earlier, the Soviet government had also clearly expressed “agreement with the basic principles of” the Atlantic Charter, which stated that the signatories “seek no aggrandizement, territorial or other… [and] desire to see no territorial changes that do not accord with the freely expressed wishes of the peoples concerned.” The Soviet Union and the United States, between Yalta and the immediate postwar months, would fiercely negotiate territorial and other parameters of power centered on the distribution of territories including both the homeland and colonies of the defeated Japanese empire and the division of Korea into Northern and Southern zones.