Background Twenty years after the "the war to end war," World War I, a far more brutal, destructive, and deadlier conflict broke out—World War II. Fought from 1939 to 1945, the Second World War included almost every nation in the world, with the major powers dividing themselves into two military alliances. On one side were the Axis powers—primarily Germany, Italy, and Japan. On the other side, the Allies—Great Britain, France, the Soviet Union, and the United States. The war turned out to be the largest and deadliest struggle in human history, resulting in 40 to 70 million deaths. As it did in the run up to World War I, the U.S. remained neutral as long as it could before joining the Allies in 1941. More than any other single incident, World War II catapulted the United States into the role of Superpower, a role that it has yet to relinquish. Most historians recognize Germany's invasion of Poland on September 1, 1939, as the start of World War II, but in some ways, the war started long before that. Adolf Hitler and his Nazi party rose to power by playing to German resentment of the harsh terms of the Treaty of Versailles, which had ended World War I. Throughout the 1930s, Hitler violated the terms of the Treaty by annexing and invading neighboring states. He also started the systematic persecution of
Jewish people and others whom he deemed undesirable, such as political dissidents, homosexuals, and Romani (Gypsies). Eventually, persecution turned into the systematic extermination of these groups known as the Holocaust. As these developments were taking place, the western powers only "appeased" Hitler in order to avoid another war. But when Hitler invaded Poland in 1939, France and Great Britain finally awoke from their slumber of appeasement and declared war on Germany on September 3, 1939. Meanwhile, in Asia during the 1930s, aggressive militarists took the reins of power in the Empire of Japan and invaded China in 1937, setting out on a course to conquer and rule Asia. Again, the western powers did nothing in response. America's Response At first, America responded to the events in Europe and Asia during the 1930s with only official declarations of neutrality. This is not to say that Americans were unconcerned about Hitler's aggression. By June 1940, the Führer managed to conquer most of Western Europe, which left Great Britain as the last great western democracy fighting alone against the holocaustic Nazi war machine. The American president, Franklin Delano Roosevelt, tried to keep Britain afloat by supplying the island nation with munitions, but such support ultimately led to German submarines attacking American ships by September 1941. Surprisingly,
though, America's official entrance into World War II did not happen because of tensions with Germany. Instead, it came because of in- creased hostilities in the Far East with Japan. Japan depended on the U.S. for major shipments of things like steel and oil in its war against China, but when Japan joined with Germany and Italy in the Tripartite Pact in September 1940 and refused to withdraw from China, as President Roosevelt demanded, the president cut off supplies to Japan. Desperate for provisions, especially oil, Japan decided that it would conquer the resource-rich regions of Southeast Asia. To do that, Japanese leaders thought it crucial to neutralize America's fleet in the Pacific at Pearl Harbor, Hawaii. On the morning of December 7, 1941—"a date which will live in infamy" as President Roosevelt called it—the Japanese launched a surprise attack on Pearl Harbor—a stunning Japanese victory that destroyed much of the American fleet and killed approximately three thousand Americans. The U.S. declared war on Japan the next day. Three days later, Italy and Germany as Japanese allies declared war on the U.S. Unlike anything else could, the attack unified Americans and instilled in them a sense of determination to win.Aftermath and Significance The U.S. military fought in all three main theaters of World War Il-The Mediterranean, Europe, and the
Pacific. American warriors played a decisive role in helping the Allies win a complete victory over the Axis powers by 1945. For the second time in the century, democracy had triumphed over tyranny. However, World War II had far more dramatic and far-reaching consequences. Even though America had entered the war in The Great Depression, the war turned the U.S. economy into the most prosperous on earth. During the war, American factories and farms were forced to produce at astonishing levels, and this continued after the war. Politically, the United States and Soviet Union emerged as the two Superpowers of the world, but with a deep- seated distrust of one other, too. The Soviet Union's state-centered communist system was in direct opposition to America's capitalist one and vice-versa. This distrust led to a fifty-year period of rivalry and struggle between the Soviet Union and United States and their respective allies called the Cold War. The Cold War did not include direct shooting between American and Soviet soldiers. The most serious conflict came in the form of proxy wars like the Korean and Vietnam Wars, which reflected America and the west's general policy of "containment" —containing the political, economic, and military influence of its former ally.Finally, World War II had an incalculable psychological impact on the world. The war ended in Japan because the atomic age began. The U.S. had developed and used atomic weapons for the first time in history on Japan. A nuclear arms race ensued and became a major part of the Cold War. As the Soviet and American blocs competed to see who could build the most powerful and most numerous nuclear weapons, for the first time in history, human beings had to face the possibility of self-extinction through a calamitous nuclear holocaust. Though the Cold War ended in 1991, in many ways, the dread of the nuclear age remains.