In 1945, on behalf of the Flensburg government, Reichsprësident Karl Doënitz signed the Treaty of Rheims at U.S. General Dwight D. Eisenhower's headquarters in France and over 100,000 surrendered German soldiers were transferred to the Allied forces preparing for Operation Unthinkable, the surprise attack on the Soviet Union.
The Treaty of Rheims is signedThe death of Franklin D. Roosevelt on the eve of the Yalta Conference had brought to office a new President that shared Winston's Churchill plan to "impose upon Russia the will of the United States and the British Empire". Not only had Stalin refused to honour the guarantees for Polish independence that had forced Britain into the war, it also became evident that his ambition extended to the whole of Eastern Europe.
The main obstacle to Operation Unthinkable was removed on April 30th when Adolf Hitler suicided with General Patton's Third Army only two blocks from the the Reich Chancellery. Because of treachery in the Nazi High Command, Hitler had been forced to nominate the German Commander-in-Chief and Grand Admiral as his successor.
Karl Doenitz was a German naval Commander who served in the Imperial German Navy during World War I, commanded the German submarine fleet during World War II, and eventually was given control of the entire Kriegsmarine. These impeccable credentials enabled Doenitz to emerge as the new Hindenburg, a rallying point for central authority who could nevertheless distance himself from the defeated regime. And the Allies needed a unified nation in order to strike the Soviet Union.
And quickly, too. Any quick success from Operation Unthinkable would be due to surprise alone. If a quick success could not be obtained before the onset of winter the assessment was that the Allies would be committed to a total war which would be protracted (in a report of 22 May 1945 an offensive operation was deemed "hazardous").