Historians have often examined the tempestuous relationship between Germany and the Soviet Union. The broad outlines of the story are well known. They alternate between amity and enmity. Long before Germany had become a “nation,” the region exerted a powerful cultural influence on Russia. Russia, Prussia, and the Austrian Empire battled over the “bloodlands” between them in the 18th Century. Otto von Bismarck, the Chancellor of a united Germany, built his foreign policy on managing the conflict between Russia and the Austrian Empire to avoid war. After his fall from power in 1890, German leaders succumbed to the “spell of power.” Their plan for war, the Schlieffen Plan, aimed to destroy Russia and France as major European powers. German war aims against Russia in the First World War culminated in the 1918 Treaty of Brest-Litovsk, which largely accomplished the pre-war ambitions. These gains were lost when the Western powers defeated Germany on the battlefield later in the year. The Allies imposed a harsh, if just, peace on Germany. It became an outcast, whose chief visible aim lay in restoring respectability. Meanwhile, the Bolshevik seizure of power, their abandonment of their allies in the separate peace at Brest-Litovsk, their repudiation of pre-war debts, and their attempts to export revolution to other countries made the Soviet Union a pariah country.
The two outcasts found a community of interest in evading international restrictions in order to revive their power. From 1922 to 1932, the German military and the Soviets cooperated on weapons development and military training. The democratic Weimar Republic chose not to know about this relationship. Initially, the German aims were short-term. Many military leaders fantasized that it would be possible to renew the lost war within a few years. To this end, they encouraged right-wing paramilitary groups like the Nazis.
The renewed war in the West did not come, but—in the crisis of the Depression—the Nazis arrived in power. Adolf Hitler, the anti-Soviet German dictator, ruptured relations with the Soviet Union. Increasingly, the two countries became at daggers drawn. In 1935, the Soviet Union formed an alliance with France; in 1936 Germany formed the Anti-Comintern Pact with Italy and Japan; from 1936 through 1938, Germany and the Soviet Union waged a proxy war in Spain. Some Westerners hoped for a deeper engagement with the Soviet Union against Nazi Germany. Others hoped that Hitler’s ferocious hostility to the Soviet Union would lead him into a bloody war of exhaustion in the East that would remove the need for the West to fight.
Suddenly, in August 1939, Germany and the Soviet Union signed a treaty that left them free to carve up Eastern Europe. Hitler later chose to attack Western Europe and then, in June 1941, the Soviet Union. Even in 1941, many Germans regretted this rejection of Russia.
 John W. Wheeler-Bennett, Brest-Litovsk: The Forgotten Peace, March 1918 (1938), and “Twenty Years of Russo-German Relations: 1919-1939” Foreign Affairs Vol. 25, #1, pp. 23-43; Hans W. Gatzke, “Russo-German military collaboration during the Weimar Republic,” American Historical Review, Vol. 63, #3 (1958), pp. 565-597; Walter Laqueur, Russia and Germany (1965); Gerhard Weinberg, Germany and the Soviet Union 1939-1941 (1972); Barbara Jelavich, St. Petersburg and Moscow: tsarist and Soviet foreign policy, 1814-1974 (1974); Harvey L. Dyck, Weimar Germany and Soviet Russia, 1926-1944 (1984); Geoffrey Roberts, The Soviet Union and the Origins of the Second World War: Russo-German Relations and the Road to War, 1933-41 (1995); Aleksandr M. Nekrich, Pariahs, partners, predators: German-Soviet relations, 1922-1941 (1997); Ian Johnson, Faustian Bargain: The Soviet-German Partnership and the Origins of the Second World War (2015).
 From 1890 to 1945 Germany’s leaders repeatedly failed to adjust aspirations to resources. Disasters followed.