In Potsdam, little real progress has been made, beyond an agreement on fulfilling the commitments made in Yalta. The main objective of the Potsdam conference was to put an end to the post-war period and to put into practice all that had been agreed in Yalta. While the Yalta meeting was rather friendly, the Potsdam conference was marked by differences of opinion that were the result of some important changes since the Yalta conference. The border of Poland became the Oder and the Neisse to the west, and the country received part of the former East Prussia. This required that millions of Germans be transferred to Germany in these regions. The Romanian, Hungarian and Bulgarian governments were already controlled by the Communists and Stalin stubbornly refused to let the Allies intervene in Eastern Europe. While in Potsdam, Truman Stalin spoke of the « new weapon » of the United States (the atomic bomb) that she wanted to use against Japan. On 26 July, the conference issued an ultimatum to Japan, which called for an unconditional surrender and, if not, threatened to launch more serious airstrikes. After Japan rejected this ultimatum, the United States dropped atomic bombs on Hiroshima and Nagasaki. The Potsdam Conference is perhaps best known for President Truman`s meeting with Stalin on July 24, 1945, during which the President announced to the Soviet leader that the United States had successfully detonated the first atomic bomb on July 16, 1945. Historians have often interpreted Truman`s somewhat firm attitude during the negotiations to mean that the U.S. negotiating team believed that the U.S.
nuclear capabilities would strengthen its bargaining power. Stalin, however, was already well informed about the American nuclear program thanks to the Soviet secret services; he stood his ground in his positions. This situation has made negotiations difficult. The leaders of the United States, Britain and the Soviet Union, who had remained allies during the war despite their differences, never met collectively again to discuss cooperation in post-war reconstruction. In the statement of the Potsdam conference on Germany, it is stated: « The intention of the Allies is to enable the German people to prepare for a possible reconstruction of their lives on a democratic and peaceful basis. » The four areas of occupation of Germany, designed at the Yalta conference, were created, each to be managed by the commander-in-chief of the Soviet, British, American or French occupation army. Berlin, Vienna and Austria were also divided into four zones of occupation. An allied supervisory board, made up of representatives of the four allies, should deal with issues relating to Germany and Austria as a whole. Their policy was dictated by the « five Ds » decided in Yalta: demilitarization, denatalization, democratization, decentralization and deindustrialization. Each Allied power had to seize repairs to its own areas of occupation, while the Soviet Union was allowed 10 to 15 percent of industrial equipment in western Germany in exchange for agricultural and other natural products in its area. US President Franklin D. Roosevelt was dead and replaced by his Vice President Harry S Truman. While Roosevelt was willing to work with Stalin, especially because he needed the USSR to join the war against Japan, Truman made little mystery of his aversion to communism and to Stalin himself.