On December7, 1941, Japanese forces crippled America’s Pacific fleet in a sneak attack on the Pearl Harbor base in Hawaii, bringing the nation into World War II. But did America ignore warnings about strike in order to inspire American outrage against Japan as the aggressor?
Tension between the US and Japan had been building steadily since 1931, when Japan invaded Manchuria. By 1937, Japanese forces had invaded China proper, and from there they hungrily eyed the Asian territories of Britain, France, Holland, and the US. When Germany subjugated France in 1940, Japan saw an opportunity. On July 24, 1941, it invaded France Indochina. In retaliation, FDR placed embargoes on all Japanese exports, except oil. Japanese ambassador Normura offered interesting oil for peace deal meanwhile commander of Japan’s fleet secretly planned an attack that would incapacitate his new enemy “On the very first day.” US added oil to the embargo, which would have soon crippled Japanese industry.
Having cracked the Japanese naval code “Purple” the US knew Japan had been tracking the US Pacific fleet. On November 25, 1941, Stimson warned FDR that Japanese attack was imminent. On December 6, the night before the attack, American intelligence had intercepted a purple message indicating Japan was going to declare war the next day. A warning was sent to Pearl Harbor base by telegraph but, tragically, the message did not arrive until after the attack had begun.