The Pearl Harbor Attack, 7 December 1941
The road to war between Japan and the United States began in the 1930s when differences over China drove the two nations apart. In 1931 Japan conquered Manchuria, which until then had been part of China. In 1937 Japan began a long and ultimately unsuccessful campaign to conquer the rest of China. In 1940, the Japanese government allied their country with Nazi Germany in the Axis Alliance, and, in the following year, occupied all of Indochina.The United States, which had important political and economic interests in East Asia, was alarmed by these Japanese moves. The U.S. increased military and financial aid to China, embarked on a program of strengthening its military power in the Pacific, and cut off the shipment of oil and other raw materials to Japan.Because Japan was poor in natural resources, its government viewed these steps, especially the embargo on oil as a threat to the nation's survival. Japan's leaders responded by resolving to seize the resource-rich territories of Southeast Asia, even though that move would certainly result in war with the United States.