History of Germany during World War I
In November 1918, with internal revolution, a stalemated war, Bulgaria and the Ottoman Empire suing for peace, Austria-Hungary falling apart from multiple ethnic tensions, and pressure from the German high command, the Kaiser and all German ruling princes abdicated. On 9 November 1918, the Social Democrat Philipp Scheidemann proclaimed a Republic, in cooperation with the business and middle classes, not the revolting workers. The new government led by the German Social Democrats called for and received an armistice on 11 November 1918; in practice it was a surrender, and the Allies kept up the food blockade to guarantee an upper hand. The war was over; the history books closed on the German Empire. It was succeeded by the democratic, yet flawed, Weimar Republic.
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."