the conquest and rout an ill-conceived British expeditionary force sent to save the Balkans. Greece fell in April 1941, a week after Yugoslavia, where 17,000 people had been killed in a single day of Luftwaffe bombing.
Mussolini’s legions had also been on the march in Africa, attacking from the Italian colony of Libya into Egypt, a former British protectorate still occupied by British troops. A British and Australian counteroffensive in December 1940 smashed an Italian army twice its size, eventually inflicting 150,000 casualties. With the Axis southern flank imperiled, Hitler again came to Mussolini’s rescue, dispatching a new Afrika Korps to Libya under a charismatic tank officer who had previously commanded the Führer’s headquarters troops in Poland. General Erwin Rommel reached Tripoli in mid-February 1941 and launched a campaign that would surge back and forth across the North African littoral for the next two years, first against the British and then against the Americans.
Two monumental events in 1941 changed the calculus of the war. On June 22, nearly 200 German divisions invaded the Soviet Union in abrogation of the nonaggression pact that Hitler and Soviet leader Joseph Stalin had signed in 1939, which had allowed a division of spoils in eastern Europe. Within a day, German attacks had demolished one-quarter of the Soviet air force. Within four months, the Germans had occupied 600,000 square miles of Russian soil, captured 3 million Red Army troops, butchered countless Jews and other civilians, and closed to within sixty-five miles of Moscow. But four months after that, more than 200,000 Wehrmacht troops had been killed, 726,000 wounded, 400,000 captured, and another 113,000 had been incapacitated by frostbite.
The second event occurred on the other side of the world. On December 7, Japanese aircraft carriers launched 366 aircraft in a sneak attack on the U.S. Navy Pacific Fleet at Pearl Harbor, sinking or damaging eight battleships at their moorings, destroying or crippling eleven other warships, and killing 2,400 Americans. Simultaneous attacks were launched on Malaya, Hong Kong, and the Philippines. In solidarity with their Japanese ally, Hitler and Mussolini quickly declared war on the United States. It was perhaps the Führer’s gravest miscalculation and, as the British historian Martin Gilbert later wrote, “the single most decisive act of the Second World War.” America would now certainly return to Europe as a belligerent, just as it had in 1917, during the Great War.
“I knew the United States was in the war, up to the neck and in to the death,” Churchill later wrote. “I went to bed and slept the sleep of the saved and thankful.”
Two years, three months, and seven days had passed since the invasion of Poland, and the United States had needed every minute of that grace period to prepare for war. Churchill’s chief military representative in Washington, Field Marshal Sir John Dill, told London that, notwithstanding the long prelude, American forces “are more unready for war than it is possible to imagine.”
In September 1939, the U.S. Army had ranked seventeenth in the world in size and combat power, just behind Romania. When those 136 German divisions conquered western Europe nine months later, the War Department reported that it could field just five divisions. Even the homeland was vulnerable: some coastal defense guns had not been test-fired in twenty years, and the Army lacked enough anti-aircraft guns to protect even a single American city. The building of the armed forces was likened to “the reconstruction of a dinosaur around an ulna and three vertebrae.”
That task had started with the 16 million men who registered for the draft in the fall of 1940, and who would expand Regular Army and National Guard divisions. By law, however, the draftees and newly federalized Guard units were restricted to twelve months of service—and only in the western hemisphere or U.S.