While most Americans anxiously watched the course of the European war, tension mounted in Asia. Taking advantage of an opportunity to improve its strategic position, Japan boldly announced a "new order" in which it would exercise hegemony over all of the Pacific. Battling for its survival against Nazi Germany, Britain was unable to resist, withdrawing from Shanghai and temporarily closing the Burma Road. In the summer of 1940, Japan won permission from the weak Vichy government in France to use airfields in Indochina. By September the Japanese had joined the Rome-Berlin Axis. As a countermove, the United States imposed an embargo on export of scrap iron to Japan.  

It seemed that the Japanese might turn southward toward the oil, tin and rubber of British Malaya and the Dutch East Indies. In July 1941 the Japanese occupied the remainder of Indochina; the United States, in response, froze Japanese assets.  

General Hideki Tojo became prime minister of Japan in October 1941. In mid-November, he sent a special envoy to the United States to meet with Secretary of State Cordell Hull. Among other things, Japan demanded that the U.S. release Japanese assets and stop U.S. naval expansion in the Pacific. Hull countered with a proposal for Japanese withdrawal from China and Indochina in exchange for the freeing of the frozen assets. The Japanese asked for two weeks to study the proposal, but on December 1 rejected it. On December 6, Franklin Roosevelt appealed directly to the Japanese emperor, Hirohito. On the morning of December 7, however, Japanese carrier-based planes attacked the U.S. Pacific fleet at Pearl Harbor, Hawaii, in a devastating, surprise attack. Nineteen ships, including five battleships, and about 150 U.S. planes were destroyed; more than 2,300 soldiers, sailors and civilians were killed. Only one fact favored the Americans that day: the U.S. aircraft carriers that would play such a critical role in the ensuing naval war in the Pacific were at sea and not anchored at Pearl Harbor.  

As the details of the Japanese raids upon Hawaii, Midway, Wake and Guam blared from American radios, incredulity turned to anger at what President Roosevelt called "a day that will live in infamy." On December 8, Congress declared a state of war with Japan; three days later Germany and Italy declared war on the United States. The nation rapidly geared itself for mobilization of its people and its entire industrial capacity. On January 6, 1942, President Roosevelt announced staggering production goals: delivery in that year of 60,000 planes, 45,000 tanks, 20,000 antiaircraft guns and 18 million deadweight tons of merchant shipping. All the nation's activities -- farming, manufacturing, mining, trade, labor, investment, communications, even education and cultural undertakings -- were in some fashion brought under new and enlarged controls. The nation raised money in enormous sums and created great new industries for the mass production of ships, armored vehicles and planes. Major movements of population took place. Under a series of conscription acts, the United States brought the armed forces up to a total of 15,100,000. By the end of 1943, approximately 65 million men and women were in uniform or in war-related occupations.  

The attack on the United States disarmed the appeal of isolationists and permitted quick military mobilization. However, as a result of Pearl Harbor and the fear of Asian espionage, Americans also committed an act of intolerance: the internment of Japanese-Americans. In February 1942, nearly 120,000 Japanese-Americans residing in California were removed from their homes and interned behind barbed wire in 10 wretched temporary camps, later to be moved to "relocation centers" outside isolated Southwestern towns. Nearly 63 percent of these Japanese-Americans were Nisei -- American-born -- and, therefore, U.S. citizens. No evidence of espionage ever surfaced. In fact, Japanese-Americans from Hawaii and the continental United States fought with noble distinction and valor in two infantry units on the Italian front. Others served as interpreters and translators in the Pacific. In 1983 the U.S. government acknowledged the injustice of internment with limited payments to those Japanese-Americans of that era who were still living.