Pearl Harbor Naval Base
The attack on Pearl Harbor was intended to neutralize the U.S. Pacific Fleet, and hence protect Japan's advance into Malaya and the Dutch East Indies, where it sought access to natural resources such as oil and rubber. War between Japan and the United States had been a possibility of which each nation had been aware (and developed contingency plans for) since the 1920s, though tensions did not begin to grow seriously until Japan's 1931 invasion of Manchuria. Over the next decade, Japan continued to expand into China, leading to all-out war between those countries in 1937. Japan spent considerable effort trying to isolate China and achieve sufficient resource independence to attain victory on the mainland; the "Southern Operation" was designed to assist these efforts.
From December 1937, events such as the Japanese attack on the USS Panay and the Nanking Massacre (more than 200,000 killed in indiscriminate massacres) swung public opinion in the West sharply against Japan and increased Western fear of Japanese expansion,[18] which prompted the United States, the United Kingdom, and France to provide loan assistance for war supply contracts to the Republic of China.
In 1940, Japan invaded French Indochina in an effort to control supplies reaching China. The United States halted shipments of airplanes, parts, machine tools, and aviation gasoline to Japan; this was perceived by Japan as an unfriendly act. The U.S. did not stop oil exports to Japan at that time in part because prevailing sentiment in Washington was that such an action would be an extreme step, given Japanese dependence on U.S. oil, and likely to be considered a provocation by Japan.
From December 1937, events such as the Japanese attack on the USS Panay and the Nanking Massacre (more than 200,000 killed in indiscriminate massacres) swung public opinion in the West sharply against Japan and increased Western fear of Japanese expansion,[18] which prompted the United States, the United Kingdom, and France to provide loan assistance for war supply contracts to the Republic of China.
In 1940, Japan invaded French Indochina in an effort to control supplies reaching China. The United States halted shipments of airplanes, parts, machine tools, and aviation gasoline to Japan; this was perceived by Japan as an unfriendly act. The U.S. did not stop oil exports to Japan at that time in part because prevailing sentiment in Washington was that such an action would be an extreme step, given Japanese dependence on U.S. oil, and likely to be considered a provocation by Japan.