“In 1935 and 1936, the U.S. Congress passed Neutrality Acts to prohibit the U.S. from selling goods to countries at war. The acts were ostensibly to protect the U.S. from falling into another conflict like World War I. President Franklin D. Roosevelt signed the acts, although he did not like them because they prohibited the U.S. from helping allies in need.
In July 1941, the U.S. completely embargoed resources to Japan and froze all Japanese assets in American entities. American policies forced Japan to the wall. With the approval of Japanese Emperor Hirohito, the Japanese Navy began planning to attack Pearl Harbor, the Philippines, and other bases in the Pacific in early December to open the route to the Dutch East Indies.
The Japanese kept diplomatic lines open with the U.S. on the off chance they could negotiate an end to the embargo. Any hope of that vanished on November 26, 1941, when U.S. Secretary of State Cordell Hull handed Japanese ambassadors in Washington, D.C. what has come to be known as the “Hull Note.”U.S.-Japanese Foreign Policies Before World War II