At the Potsdam Conference, the leaders of the United States, Great Britain and the Soviet Union—the “Big Three” powers who had defeated Nazi Germany—met in the city of Potsdam near Berlin. Their meeting lasted from July 17 to August 2, 1945, during what was a crucial moment in defining the post-World War II balance of power. The summit also gave an early hint of the tensions that would develop between the U.S. and the Soviet Union, which eventually led to a Cold War struggle that lasted for more than four decades.
The conference was attended by U.S. President Harry S. Truman, Soviet leader Joseph Stalin and British Prime Minister Winston Churchill, who was abruptly replaced on July 26 by his successor Clement Attlee, after results of the British election were announced.
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Truman in Europe
The conference came just three months after Truman took over the presidency following the death of his predecessor, Franklin D. Roosevelt. As historian David McCullough recounts in his 1992 biography, Truman, the new president wasn’t eager to go so soon for his first meeting with the other two leaders of the Big Three that had defeated Nazi Germany.
“I have a briefcase filled up with information on past conferences and suggestions on what I’m to do and say,” he wrote in a letter to his mother and sister. Nevertheless, he sailed to Europe on the on the U.S. cruiser Augusta, his first visit to the continent since he had fought in World War I.
After Truman arrived, he got a chance to tour the conquered city of Berlin, where he was disturbed by hordes of homeless civilians, many of them children, struggling to survive in the bombed-out ruins. Truman later described Berlin as “a ghost city” in a radio address to Americans.
Germany's Fate After World War II
Germany’s fate after the war was an important topic of the conference. According to the U.S. State Department’s history of the event, Stalin had pressured FDR at the previous Yalta Conference in February 1945 to force the defeated Germans to pay heavy postwar reparations, half of which would go to the Soviet Union. Roosevelt had agreed to that demand.
But Truman, who was keenly aware that similar economic punishment inflicted upon the Germans after World War I had led to the rise of Adolf Hitler and Nazism, was determined not to make the same mistake. Ultimately, the Allies worked out a deal in which the Soviets got to take German industrial machinery from their occupation zone.
READ MORE: How the ‘Big Three’ Teed Up the Cold War at the Yalta Conference
The Big Three worked out many of the details of the postwar order in the Potsdam Agreement, signed on August 1. They confirmed plans to disarm and demilitarize Germany, which would be divided into four Allied occupation zones controlled by the United States, Great Britain, France and the Soviet Union.
They also went ahead with plans to drastically remake German society, by repealing laws passed by the Nazi regime and removing Nazis from the German education and court systems, and to arrest and try Germans who had committed war crimes.
They also approved the formation of a Council of Foreign Ministers, which would act on behalf of the United States, Great Britain, the Soviet Union and China to write peace treaties with former German allies, such as Italy and Bulgaria.
The Potsdam Agreement also called for Poland, Czechoslovakia and Hungary, which wanted to expel the ethnic German populations within their borders, to do so “in an orderly and humane manner.”
The idea was to head off a massive influx of refugees into a Germany where existing residents already were having difficulty getting by. But the redrawing of Poland’s border with Germany was left unresolved.
READ MORE: As the Allies Closed in on Hitler, They Jockeyed for Future World Dominance
Pressuring Japan to Exit the War
Another important purpose of the Potsdam Conference was to pressure Japan, which was still in the war. To that end, on July 26, the United States and Great Britain, along with China, issued the Potsdam Declaration, which threatened a massive aerial and naval attack and land invasion that would “strike the final blows upon Japan,” unless the Japanese agreed to surrender.
The declaration laid out the Allies’ non-negotiable terms for peace, which included unconditional surrender and disarming of the Japanese military, occupation of Japan “until there is convincing proof that Japan’s war-making power is destroyed” and trials for Japanese war criminals, and creation of a democratic system of government with freedom of speech and other rights for citizens.
In exchange, Japan would be allowed to maintain industries that were unrelated to war and have access to raw materials, and eventually would be permitted to resume international trade.
Just before the conference began, Truman got the secret news of the successful Trinity test of the atomic bomb by Manhattan Project scientists, and apparently decided to use that knowledge to give him a negotiating advantage over Stalin.
At the close of an afternoon meeting of July 24, Truman walked over to Stalin and told him quietly that the U.S. had developed “a new weapon of unusual destructive force,” more powerful than any known bomb, and planned to use it soon unless Japan surrendered.
Probably to Truman’s surprise, Stalin didn’t seem too interested in the revelation. “All he said was that he was glad to hear it, and hoped we would make ‘good use of it against the Japanese,’” Truman later recalled. The reason behind Stalin's mild reaction was that he had at least two spies inside the Manhattan project and already knew about the U.S. atomic weapons program. The Soviet leader didn’t budge from his negotiating positions.
Potsdam was the final time that leaders of the United States, Great Britain and the Soviet Union, who had maintained a tense alliance despite their differences during the war, would meet to discuss postwar cooperation.
“The Potsdam Conference, 1945.” Office of the Historian, U.S. Department of State.
Truman, by David McCullough, 1992, June 1992. Simon & Schuster.
“The Potsdam Agreement: Protocol of the Proceedings,” August 1, 1945. NATO.
“Foreign Relations of the United States: Diplomatic Papers, the Conference of Berlin (The Potsdam Conference),” 1945, Volume II, U.S. Department of State.
‘He is honest — but smart as hell’: When Truman met Stalin,” by Kristine Phillips, July 17,2018, Washington Post.
“Radio Report to the American People on the Potsdam Conference, August 09, 1945.” The American Presidency Project, University of California, Santa Barbara.