World War II is appropriately called “Hitler’s war.” Germany was so extraordinarily successful in the first two years that Hitler came close to realizing his aim of establishing hegemony in Europe. But his triumphs were not part of a strategic conception that secured victory in the long run. Nonetheless, the early successes were spectacular. After the defeat of Poland within a month, Hitler turned his attention westward. He believed that it was necessary to defeat Britain and France before he could again turn eastward to the territories that were to become the “living space” for his new empire. The attack on the Western Front began in the spring of 1940. Hitler took Denmark and Norway during the course of a few days in April, and on May 10 he attacked France, along with Luxembourg, Belgium, and The Netherlands. Once again his armies achieved lightning victories; Luxembourg, Belgium, and The Netherlands were overrun in a few days, and France capitulated on June 21. Only the British, now alone, obstructed Hitler’s path to total victory in the west.
Hitler determined that he could take Britain out of the war with air power. German bombers began their attack in August 1940, but the British proved intractable. The vaunted German air force (Luftwaffe) failed to bring Britain to its knees partly because of the strength of the British air force, partly because the German air force was ill-equipped for the task, and partly because the British were able to read German code (see Ultra). Yet Hitler had been so confident of a quick victory that, even before the attack began, he had ordered his military planners to draw up plans for an invasion of the Soviet Union. The date he had set for that invasion was May 15, 1941.
Although the defeat of the Soviet Union was central to Hitler’s strategic objective, during the early months of 1941 he allowed himself to be sidetracked twice into conflicts that delayed his invasion. In both instances he felt obliged to rescue his ally Mussolini from military difficulties. Mussolini had invaded Greece in October 1940, despite the fact that he was already in difficulty in North Africa, where he was unable to cut off Britain’s Mediterranean lifeline in Egypt. In February 1941 Hitler decided to reinforce Mussolini in North Africa by sending an armoured division under the command of General Erwin Rommel. When Mussolini’s invasion of Greece also bogged down, Hitler again decided to send reinforcements. To reach Greece, German troops had to be sent through the Balkan countries, all of them officially neutral. Hitler managed to bully these countries into accepting the passage of German troops, but on March 27 a coup in Yugoslavia overthrew the government, and the new rulers reneged on the agreement. In retaliation Hitler launched what he called Operation Punishment against the Yugoslavs. Yugoslav resistance collapsed quickly, but the effect was to delay for another month the planned invasion of the Soviet Union.