Pearl Harbor
Some claim that the Japanese attack on December 7, 1941, on the U.S. naval base at Pearl Harbor on Oahu Island, Hawaii was allowed to happen in order to justify the United States entry into World War II. American public opinion prior to the attack was strongly against entering the war. The conspiracy theorists assert that President Franklin D. Roosevelt was aware of Japan’s intention to attack but allowed it to occur to shift public opinion in favour of entering the war.
Most historians disagree with the “back-door to war” theory. President Roosevelt’s government in the months leading up to the attack had taken a number of non-military measures against the Japanese. In July 1941, following Japan’s occupation of French Indochina, the government froze Japanese assets in the United States and placed an embargo on petroleum shipments and other vital war materials to Japan. By late 1941 the United States had severed virtually all commercial and financial relations with the Japanese government.
President Roosevelt believed prior to the attack on Pearl Harbor, that a war with Japan would hinder American aid to Britain and therefore lengthen its struggle against Germany. At a cabinet meeting on November 7, 1941, Roosevelt said that his administration should “strain every nerve to satisfy and keep on good relations” with the Japanese negotiators. He advised the Secretary of State, Cordell Hull, to do everything in his power to not let the negotiations with the Japanese “deteriorate and break-up,” and said, “let us make no move of ill will, let us do nothing that will precipitate a crisis.”
While it is true that President Roosevelt and his advisers did foresee a Japanese attack on December 6-7, 1941, conflicting intelligence about the location of the attack meant that they could not tell with certainty where it would take place. U.S. Military leaders believed that the fleet located in Pearl Harbour would have been more of a deterrent than a target to the Japanese, which is one of the reasons they were caught by surprise by the attack. Similarly, U.S. Military leaders underestimated Japanese air and naval forces, erroneously thinking that the Japanese did not have the capability to mount a successful attack on Pearl Harbour.
Also, most historians doubt that President Roosevelt, himself a former assistant secretary of the Navy, would have jeopardised so much of the U.S. fleet by allowing an attack on Pearl Harbor.