To suggest that the victorious allied countries from World War II learned lessons from their failures after World War I would be an enormous understatement.
Following the armistice that ended the fighting in World War I, the Allied powers (Great Britain, France and the United States) compelled Germany to sign a peace treaty, the Treaty of Versaille, that imposed conditions on it that German leaders and its public found extremely unpalatable. These conditions included German acknowledgement of its responsibility for the war, the payment of reparations, the relinquishment of German territory that included large German populations, and tight restrictions on its ability to rebuild its armed forces.
These conditions, imposed on a defeated country that nonetheless continued to possess considerable industrial power and a large pool of capable manpower, to say nothing of very strong nationalistic sentiments, would prove increasingly untenable. German bitterness over its treatment at the hands of the Allied powers, despite the latter's culpability in the origins of the war, combined with the economic devastation wrought by the Great Depression and high levels of unemployment that resulted provided the seeds for the war that would follow.
The rise of Adolf Hitler and the National Socialist Party (the Nazis) was facilitated in no small part by German resentment of its treatment. The Treaty of Versaille was looked upon as the source of national humiliation at the hands of the British and the French.
As the eventual outcome of World War II approached, there was a great deal of often contentious debate among the Allied powers regarding the treatment of Germany after its defeat was final. Each of the allies approached deliberations over Germany's fate from their own unique perspective. Not surprisingly, the French and Russians, both of whom endured years of brutal occupation, especially the Russians, were less inclined towards leniency. The Soviet Union emerged from the war a major power, as did the United States, but disagreements over Germany ran deep. Nevertheless, conferences among allied leaders at Yalta in February 1945 and later that year in Potsdam Germany saw broad agreement on the outlines of a postwar Europe, with Germany at the center.
The resultant division of Germany, which would last until the end of the Cold War in 1989, reflected the depth of disagreement over how the defeated Germany should be treated. The British and Americans in particular had learned from the failure of the Treaty of Versaille and, combined with concerns about Soviet plans for Europe, wanted Germany rebuilt and prosperous, albeit with reasonable limitations on its ability to rearm and controls on its political development. Subsequently, West Germany would emerge as a strong, prosperous democracy. The Soviet Union wanted Germany kept weak and subservient. The resultant East German state would become a microcosm of Stalin's police state to the east.