Modern history

World War II



One month after Japan attacked the U.S. naval base at Pearl Harbor on December 7, 1941, and the United States entered World War II, President Franklin Roosevelt approved a full-scale effort to develop an atomic bomb. As scientific director of this top-secret program, called the Manhattan Engineering District Project, physicist J. Robert Oppenheimer orchestrated the work of more than 3,000 scientists, technicians, and military personnel at the Los Alamos Laboratories near Santa Fe, New Mexico. The thirty-seven-year-old Oppenheimer, the son of German American Jews, had studied theoretical physics in England and Germany and then returned to the United States to teach physics. He was also interested and engaged in world events. When the Nazis began persecuting German Jews in the early 1930s, Oppenheimer helped Jews gain asylum in the United States.

On July 16, 1945, Oppenheimer and his team successfully tested their new weapon. The explosion, which had a force equal to more than 18,000 tons of TNT, lit up the predawn sky with a blast so powerful that it broke a window 125 miles away and so bright that a blind woman claimed she saw a flash of light. A mushroom cloud shot up 41,000 feet into the sky over ground zero, where a 1,200-foot-wide crater had formed. Oppenheimer understood that the world had been permanently transformed. Quoting from Hindu scriptures, he remembered thinking at the moment of the explosion, "I am become death, destroyer of worlds."

On August 6, 1945, Army Air Corps planes dropped an atomic bomb on the Japanese city of Hiroshima and three days later another one on Nagasaki, resulting in the deaths of more than 200,000 civilians. Profoundly shaken by the death and destruction his efforts had produced, Oppenheimer observed: "If atomic bombs are to be added to the arsenals of a warring world, or to the arsenals of nations preparing for war, then the time will come when mankind will curse the names of Los Alamos and Hiroshima."

While Oppenheimer and his team remained cloistered at Los Alamos, Fred Korematsu and some 112,000 Japanese Americans lived in internment camps, imprisoned for no other reason than their Japanese ancestry. Born in Oakland, California, in 1919 to Japanese immigrants, Fred and his three brothers grew up like many first-generation Americans. Fred's parents spoke Japanese at home and maintained the cultural traditions of their native land, while their sons learned English in public school, ate hamburgers, and played football and basketball like other children their age. After graduating from high school in 1938, Korematsu worked on the Oakland docks as a welder.

After the 1941 bombing of Pearl Harbor, residents on the West Coast turned their anger on the Japanese and Japanese Americans living among them. As assimilated as Fred Korematsu and many other Nisei (the U.S.-born children of Japanese immigrants) had become, white Americans doubted their loyalty and viewed them as a threat to national security. Korematsu could no longer get a haircut in a white-owned barbershop; the Boilermakers Union expelled him, and he lost his job as a welder; and he was not allowed to join the U.S. coast guard because of his race.

These indignities foreshadowed events to come. On March 21, 1942, President Roosevelt issued Executive Order 9066 authorizing military commanders on the West Coast to take any measures necessary to promote national security. Consequently, officials imposed a curfew on Japanese Americans, excluded them from designated areas, and prohibited them from traveling more than twenty-five miles from their homes. On May 9, the military ordered Korematsu's family to report to Tanforan Racetrack in San Mateo, from which they would be transported to internment camps throughout the West. Although the rest of his family complied with the order, Fred refused. He adopted the name "Clyde Sarah" and claimed to be of Spanish-Hawaiian ancestry. However, Korematsu's efforts to resist internment failed. Three weeks later, he was arrested and later transferred to the Topaz internment camp in south-central Utah. Found guilty of violating the original evacuation order, Korematsu received a sentence of five years of probation. When he appealed his conviction to the U.S.

Supreme Court in 1944, the high court upheld the verdict. By the time the first atomic bomb exploded over Hiroshima, the government had closed down the internment camp where Fred Korematsu lived, and he had regained his freedom.

Woman working at the Republic Drill and Tool Company in Chicago, Illinois, 1942. Library of Congress

THE AMERICAN HISTORIES of both Fred Korematsu and J. Robert Oppenheimer were shaped by the profound changes brought about by war. Korematsu was subjected to the full force of anti-Japanese sentiment that followed the attack on Pearl Harbor, while Oppenheimer played a key role in developing a weapon that he feared would lead to the destruction of mankind. Both men experienced a mixture of hope and uneasiness as they looked ahead to the postwar world.

The war that these two men experienced in such different ways marked a critical point for the United States in the twentieth century. World War II finally ended the Great Depression, cementing the trend toward government intervention in the economy that had begun with the New Deal. With the war fought almost entirely on foreign soil, the United States converted its factories to wartime production and became the “arsenal of democracy,” putting millions of Americans to work in the process, including African Americans, other minorities, and women. All Americans contributed to the war effort, whether they wanted to or not, through rationing and higher taxes. Overseas, soldiers fought fierce battles in Europe, Africa, and Asia. The combined military power of the Allies, led by the United States, Great Britain, and the Soviet Union, finally defeated the Axis nations of Germany, Italy, and Japan, but not until the fighting had killed 60 to 70 million people, more than half of whom were civilians, and ushered in the Atomic Age.

The Road toward War

The end of World War I did not bring peace and prosperity to Europe. The harsh peace terms imposed on the Central Powers in 1919 left the losers, especially Germany, deeply resentful. The war saddled both sides with a huge financial debt and produced economic instability, which contributed to the Great Depression. In the Far East, Japanese invasions of China and Southeast Asia threatened America’s Open Door policy (see chapter 20). The failure of the United States to join the League of Nations dramatically reduced the organization’s ability to maintain peace and stability. German expansionism in Europe in the late 1930s moved President Roosevelt and the nation toward war, but it took the Japanese attack on Pearl Harbor to bring the United States into the global conflict.

The Growing Crisis in Europe

Despite its failure to join the League of Nations, the United States did not withdraw from international affairs behind a wall of total isolationism in the 1920s. It participated in arms control negotiations; signed the Kellogg-Briand Pact, which outlawed war as an instrument of national policy but proved unenforceable; and expanded its foreign investments in Central and Latin America, Asia, the Middle East, and western Europe. In 1933 a new possibility for trade emerged when the Roosevelt administration extended diplomatic recognition to the Soviet Union (USSR).

Overall, the country did not retreat from foreign affairs so much as it refused to enter into collective security agreements that would restrain its freedom of action. To the extent that American leaders practiced isolationism, they did so mainly in the political sense of rejecting internationalist organizations such as the League of Nations and the World Court, institutions that might require military cooperation to implement their decisions.

The experience of World War I had reinforced this brand of political isolationism, which was reflected in an outpouring of antiwar sentiments in the late 1920s and early 1930s. Best-selling novels like Ernest Hemingway’s Farewell to Arms (1929), Erich Maria Remarque’s All Quiet on the Western Front (1929), and Dalton Trumbo’s Johnny Got His Gun (1939) presented graphic depictions of the horror and futility of war. Beginning in 1934, Senate investigations chaired by Gerald Nye of North Dakota concluded that bankers and munitions makers—“merchants of death” as one contemporary writer labeled them—had conspired to push the United States into war in 1917. Nye’s hearings appealed to popular antibusiness sentiment in depression-era America.

Following the Nye committee hearings, Congress passed a series of Neutrality Acts, each designed to make it more difficult for the United States to become entangled in European armed hostilities. In 1935 Congress prohibited the sale of munitions to either warring side and authorized the president to warn Americans against traveling on passenger liners of belligerent nations. The following year, lawmakers added private loans to the ban, and in 1937 they required belligerents to pay cash for nonmilitary purchases and ship them on their own vessels—so-called cash-and-carry provisions.

Events in Europe, however, made U.S. neutrality ever more difficult to maintain. After rising to power as chancellor of Germany in 1933, Adolf Hitler revived Germany’s economic and military strength despite the Great Depression. Hitler installed National Socialism (Nazism) at home and established the empire of the Third Reich abroad. The Führer (Leader) whipped up patriotic fervor by scapegoating and persecuting Communists and Jews. To garner support for his actions, Hitler manipulated German feelings of humiliation for losing World War I and having been forced to sign the “war guilt” clause (see chapter 20) and pointed to the disastrous effects of the country’s inflation-ridden economy. In 1936 Hitler sent troops to occupy the Rhineland between Germany and France in blatant violation of the Treaty of Versailles.

Hitler did not stop there. Citing the need for more lebensraum (space for living) for the Germanic people, he pushed for German expansion into eastern Europe. In March 1938, he forced Austria to unite with Germany. In September of that year, Hitler signed the Munich Accord with Great Britain and France, allowing Germany to annex the Sudetenland, the mainly German-speaking, western region ofCzechoslovakia. Hitler still wanted more land and was convinced that his western European rivals would not stop him, so in March 1939 he sent German troops to invade and occupy the rest of Czechoslovakia. Hitler proved correct; Britain and France did nothing in response, in hopes that he would stop with Czechoslovakia—what critics of inaction called “appeasement.”

Hitler’s Italian ally, Benito Mussolini, joined him in war and conquest. In 1935 Italian troops invaded Ethiopia; deposed its leader, Emperor Haile Selassie; and occupied the small African nation. The following year, both Germany and Italy intervened in the Spanish civil war, providing military support for General Francisco Franco in his effort to overthrow the democratically elected, socialist republic of Spain. While the United States and Great Britain remained on the sidelines, only the Soviet Union officially assisted the Loyalist defenders of the Spanish republic. In violation of American law, private citizens, many of whom were Communists, volunteered to serve on the side of the Spanish Loyalists and fought on the battlefield as the Abraham Lincoln Brigade. Other sympathetic Americans, such as J. Robert Oppenheimer, feared the spread of dictatorships and provided financial assistance for the anti-Franco government. Despite these efforts, Franco’s forces seized control of Spain in early 1939, another victory for Hitler and Mussolini.

The Challenge to Isolationism

As Europe drifted toward war, public opinion polls revealed that most Americans wanted to stay out of any European conflict. The president, however, thought it likely that the United States would eventually need to assist the Western democracies. Given the United States’ economic dominance in the world and its dependence on international commerce, Roosevelt feared that Germany and Italy threatened a stable world order. Still, Roosevelt had to tread lightly in the face of the Neutrality Acts that Congress had passed between 1935 and 1937 and overwhelming public opposition to American involvement in Europe.

Germany’s aggression in Europe eventually led to full-scale war. When Germany invaded Poland in September 1939, Britain and France declared war on Germany and Italy. Just before the invasion, the Soviet Union had signed a nonaggression agreement with Germany, which carved up Poland between the two nations and permitted the USSR to occupy the neighboring Baltic states of Latvia, Lithuania, and Estonia. Soviet leader Joseph Stalin had few illusions about Hitler’s ultimate design on his own nation, but he concluded that by signing this pact he could secure his country’s western borders and buy additional time. (In June 1941, the Germans broke the pact and invaded the Soviet Union.)

Roosevelt responded to the outbreak of war by reaffirming U.S. neutrality. Unlike Woodrow Wilson, however, he recognized that this position would be hard to maintain, asserting, “This nation will remain a neutral nation, but I cannot ask that every American remain neutral in thought as well,” and “Even a neutral cannot be asked to close his mind or close his conscience.” Despite his sympathy for the Allies, which most Americans had come to share, the president stated his hope that the United States could stay out of the war: “Let no man or woman thoughtlessly or falsely talk of Americans sending its armies to European fields.”

With the United States on the sidelines, German forces marched toward victory. By the spring of 1940, German armies had launched a blitzkrieg (lightning war) across Europe, defeating and occupying Denmark, Norway, the Netherlands, Belgium, and Luxembourg. The greatest shock occurred in June 1940 when France fell to the German onslaught and Nazi troops marched into Paris. Britain now stood virtually alone, and its position seemed tenuous. The British had barely succeeded in evacuating their forces from France by sea when the German Luftwaffe (air force) began a relentless bombing campaign on London and other targets in the Battle of Britain.

With German victories mounting, committed opponents of American involvement in foreign wars organized the America First Committee. Gerald Nye helped found the organization, which attracted New Deal critics such as Father Charles Coughlin and William Lemke; business leaders who opposed Roosevelt, such as Sears, Roebuck head Robert Wood; and aviation hero Charles A. Lindbergh, who admired what Hitler had accomplished in building up the Luftwaffe. America First tapped into the feeling of isolationism and concern among a diverse group of Americans who did not want to get dragged into another foreign war.

The surrender of France and the Battle of Britain drastically changed Americans’ attitude toward entering the war. Before Germany invaded France, 82 percent of Americans thought that the United States should not aid the Allies. After France’s defeat, in a complete turnaround, some 80 percent ofAmericans favored assisting Great Britain in some way, though most expected that this aid would lead to further U.S. involvement. However, four out of five Americans polled opposed immediate entry into the war. As a result, the politically astute Roosevelt portrayed all U.S. assistance to Britain as a way to prevent American military intervention by allowing Great Britain to defeat the Germans on its own.

From September 1940 to November 1941, the Roosevelt administration helped Britain in any way it could, short of going to war against Germany. On September 2, 1940, the president sent fifty obsolete destroyers to the British in return for leases on British naval bases in Newfoundland, Bermuda, and the British West Indies. These aging warships did not have much military value, but they provided a great morale boost to the British, who were being pounded by German air attacks. Two weeks later, on September 16, Roosevelt persuaded Congress to pass the Selective Service Act, the first peacetime military draft in U.S. history, which quickly registered more than 16 million men.

This political maneuvering came as Roosevelt campaigned for an unprecedented third term in 1940. He defeated the Republican Wendell Willkie, a Wall Street lawyer who shared Roosevelt’s anti-isolationist views. However, both candidates accommodated voters’ desire to stay out of the European war, and Roosevelt went so far as to promise American parents: “Your boys are not going to be sent into any foreign war.”

Roosevelt’s campaign promises did not halt the march toward war. Roosevelt succeeded in pushing Congress to pass the Lend-Lease Act in March 1941. With Britain running out of money and its shipping devastated by German submarines, this measure circumvented the cash-and-carry provisions of the Neutrality Acts. The United States would lend or lease equipment, but no one expected the recipients to return the used weapons and other commodities. As one critic of the act declared, “Lending war equipment is a good deal like chewing gum, you don’t really want it back!” To protect British ships carrying American supplies, the president extended naval and air patrols in the North Atlantic. In response, German submarines began sinking U.S. ships. By May 1941, Germany and the United States were engaged in an undeclared naval war.

The United States Enters the War

Financially, militarily, and ideologically, the United States had aligned itselfwith Britain, and Roosevelt expected that the nation would soon be formally at war. After passage of the Lend-Lease Act, American and British military planners agreed that defeating Germany would become the top priority if the United States entered the war. In August 1941, Roosevelt and British prime minister Winston Churchill met in Newfoundland, where they signed the Atlantic Charter, a lofty statement of war aims that included principles of freedom of the seas, self-determination, free trade, and “freedom from fear and want”—ideals that laid the groundwork for the establishment of a postwar United Nations. At the same meeting, Roosevelt promised Churchill that the United States would protect British convoys in the North Atlantic as far as Iceland while the nation waited for a confrontation with Germany that would rally the American public in support of war. The president got what he wanted. After several attacks on American ships by German submarines in September and October, the president persuaded Congress to repeal the neutrality legislation of the 1930s and allow American ships to sail across the Atlantic to supply Great Britain. By December, the nation was close to open war with Germany.

The event that finally prompted the United States to enter the war, however, occurred not in the Atlantic but in the Pacific Ocean. For nearly a decade, U.S. relations with Japan had deteriorated over the issue of China’s independence. American Christian missionaries had established their presence in China, and since the turn of the twentieth century the U.S. government had promoted the Open Door policy to protect its access to Chinese markets. The United States did little to challenge the Japanese invasion and occupation of Manchuria in 1931, but after Japanese armed forces moved farther into China in 1937, Roosevelt took action. The president skirted the Neutrality Acts by refusing to declare war, but he did supply arms to China. When a bombing raid by Japanese planes inadvertently sank the U.S. gunboat Panay in the Yangtze River and killed two sailors, Japan apologized, thereby temporarily reducing tensions between the two countries.

Yet relations between Japan and the United States did not substantially improve. In 1940 the Japanese government signed the Tripartite Pact with Germany and Italy, which created a mutual defense agreement among the Axis powers. That same year, Japanese troops invaded northern Indochina, and Roosevelt responded by embargoing sales of aviation fuel and scrap metal, products that Japan needed for war. This embargo did not deter the Japanese; in July, they occupied the remainder of Indochina to gain access to the region’s natural resources. The Roosevelt administration retaliated by freezing Japanese assets and cutting off all trade with Japan. The two countries maneuvered to the edge of war.

On the quiet Sunday morning of December 7, 1941, Japan attacked the U.S. Pacific Fleet stationed at Pearl Harbor in Honolulu, Hawaii. This surprise air and naval assault killed more than 2,400 Americans and damaged eight battleships, three cruisers, three destroyers, and nearly two hundred airplanes. The bombing raid abruptly ended isolationism and rallied the American public behind President Roosevelt, who pronounced December 7 “a date which will live in infamy.” The next day, Congress overwhelmingly voted to go to war with Japan, and on December 11 Germany and Italy declared war on the United States in response. In little more than a year after his reelection pledge to keep the country out of war, Roosevelt sent American men to fight overseas.


• How did American public opinion shape Roosevelt's foreign policy in the years preceding U.S. entry into World War II?

• What events in Europe and the Pacific ultimately brought the United States into World War II?

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