The Potsdam Conference was the longest of the Allied wartime conferences. The French did not participate, as both the Soviet and American governments saw no reason to invite them. Many of the agreements reached on the German question would subsequently founder on French opposition. The French government did not feel bound by decisions in which it had not participated, and French vetoes quickly blocked the implementation of those portions of the Potsdam agreements which called for the administrative and economic unity of Germany. The question of Germany, however, was but one of two dominating the conference; the other was the continued war with Japan. The Americans as well as the British wanted a timely entrance of Russia which would tie down the Japanese forces in Manchuria and northern China. The Soviet Union would enter the Pacific War on the 15th of August 1945.
There were three practical issues about Germany facing the Potsdam Conference. One was the establishment of a government machinery, the second was that of borders, and the third reparations. On the first, agreement was reached on an administration which would be directed and controlled by an Allied Control Council (ACC), with each zonal commander able to act on his own if no agreement or policy were reached. Because of Soviet insistence, the future border between Poland and Germany was fixed on the western Neisse, actually turning that area, along with the rest of eastern Germany (except for northern East Prussia) over to Polish administration. The Soviets also wanted massive reparations.
Other issues were at least partly worked out at Potsdam. There was to be a Council of Foreign Ministers to start meeting to prepare the peace treaties, with the first session scheduled for London in September. Preliminary agreements were not reached on the treaty with Italy - the most important after the treaty with Germany - but the Soviet Union did agree to put the Italian treaty at the head of the agenda and to support Italy's admission to the United Nations.
By the time of the Potsdam meeting, both the British and American governments were reluctantly moving toward an acceptance of the new Polish communist government, and they agreed to let it take over former Polish assets abroad. They were, however, not prepared to agree to the requested forced repatriation of the Polish soldiers who had fought alongside them against the Germans.
On the way to Potsdam, US President Harry Truman learned of the successful testing of an atomic bomb in New Mexico. He now obtained British Prime Minister Winston Churchill's agreement to tell Stalin about it. Truman was hopeful that the bomb would end the war with Japan quickly. Although he doubted that the Japanese would respond to any appeal for a prompt surrender, Truman was greatly concerned about the casualties and destruction the new weapon would cause and therefore wanted ‘a warning statement advising the Japanese to surrender and save lives’. This concern led to the Potsdam Declaration which called on Japan to surrender, a call which they dismissed.
As the Allied leaders left Potsdam for their respective countries, they could look back on a terrible struggle which had finally ended in complete victory over Hitler's Germany and its European allies. But the very completeness of that victory left them both in full control of a devastated continent and face to face with each other in its center.