Japan lacked many of the natural resources needed to feed its industries. Instead of expanding trade, the Japanese expanded their empire.
The Japanese seized Manchuria in 1931, and began a war against China in 1937.
President Roosevelt and Secretary of State Cordell Hull shut off American trade in an effort to force the Japanese to end their hostilities against China. This made the Japanese even more aggressive. They had long coveted the resource-rich British and Dutch colonies of Southeast Asia, and as the U.S. trade embargo tightened, the Japanese increasingly looked southward for raw materials and strategic resources.
Only the United States stood in Japan's path. The U.S. Pacific Fleet at Pearl Harbor was the only force capable of challenging Japan's navy, and American bases in the Philippines could threaten lines of communications between the Japanese home islands and the East Indies. Every oil tanker heading for Japan would have to pass by American-held Luzon. From these needs and constraints, Japan's war plans emerged.
First, its navy would neutralize the American fleet with a surprise attack on Pearl Harbor. Japan would also seize America's central Pacific bases at Guam and Wake islands and invade the Philippines. With American naval power crippled, Japan's military would be free to seize Burma, Malaya, Singapore, and the Dutch East Indies in a series of rapid amphibious operations. Japan would then establish a defensive ring around its newly conquered empire by fortifying islands in the south and the central Pacific.
Japan's leaders were convinced that Americans, once involved in the European war, would be willing to negotiate peace in the Pacific.
On December 7, 1941, Japan paralyzed the Pacific Fleet in its attack on Pearl Harbor. In the Philippines, Japanese fliers destroyed most of MacArthur's air force on the ground. Freed of effective opposition, Japanese forces took Burma, Malaya, Singapore, and the Dutch East Indies in rapid succession. By March 1942 the Japanese had conquered an empire.
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