German Empire
The high command under Paul von Hindenburg and Erich Ludendorff increasingly controlled the country, but in October after the failed offensive in spring 1918, the German armies were in retreat, allies Austria-Hungary and the Ottoman Empire had collapsed, and Bulgaria had surrendered. The Empire collapsed in the November 1918 Revolution with the abdications of its monarchs. This left a postwar federal republic and a devastated and unsatisfied populace, which later led to the rise of Adolf Hitler and Nazism.
Federalism
Already the Holy Roman Empire, the Confederation of the Rhine, the German Confederation, the North German Confederation, the German Empire and the Weimar Republic were federal complexes of territories of different political structures. Modern Germany abandoned federalism only during Nazism (1933–1945, only de facto but not de jure) and in the German Democratic Republic (1952–1990). Adolf Hitler viewed federalism as an obstacle to his goals. As he wrote in "Mein Kampf", "National Socialism must claim the right to impose its principles on the whole German nation, without regard to what were hitherto the confines of federal states."