Japan attacked Pearl Harbor. The US was trying to avoid being sucked into the war although they were giving relief supplies to the allies. The Japanese attacked the US at Pearl Harbor in Hawaii because of the trade embargo set as punishment for Japan's invasions of China and French Indochina, Japan was running out of oil fast in 1941. Planners predicted that they would not last far into 1942 before their military shut down, not good for an expansionist military dictatorship.