Interwar Europe and the Slide to War

The men running Britain and France in the 1930s had lived through the trenches. That memory produced appeasement: the policy of granting an aggressor's demands to avoid war. Each German move was framed as a one-time correction of an unfair treaty rather than the first step of a plan, so each was tolerated. In 1935 Hitler announced rearmament, banned by Versailles. In 1936 he remilitarized the Rhineland, a demilitarized buffer zone, and no one moved to stop him. In 1938 he annexed Austria in the Anschluss. Each step drew protest but no force, which taught Hitler that the Western powers would not fight.

Munich in September 1938 was appeasement's clearest moment. Hitler demanded the Sudetenland, the German-speaking border region of Czechoslovakia. Britain and France met with Germany and Italy, left Czechoslovakia out of the room, and let the annexation go through in exchange for Hitler's word that he wanted no more territory. He took the rest of Czechoslovakia six months later. Meanwhile the Spanish Civil War, 1936 to 1939, let Germany and Italy test the machinery of the next war on someone else's soil: the bombing of Guernica previewed terror from the air, while Hitler backed Franco and the Soviet Union backed the Republic, turning Spain into a proxy fight between fascism and its opponents.

By August 1939 appeasement had run out of room, and Hitler needed to neutralize the Soviet Union before moving on Poland. The Nazi-Soviet Pact gave both sides what they needed right then: Hitler a free hand in the west without a two-front war, Stalin time and territory. Its secret protocol split Poland and assigned the Baltic states and Bessarabia to Soviet influence. Germany invaded Poland days later, and the war the whole decade had tried to postpone began.