FDR Knew What Was Coming at Pearl Harbor?

The rulers of Japan and Germany, rather than Franklin Roosevelt, chose the moment at which the United States would enter the world war. Japan had decided back in early July to undertake the southward advance at the risk of war with the United States, the Japanese Navy had insisted on including an attack on the United States in its military plans, and Hitler had decided to declare war if Japan attacked. But Roosevelt obviously did not shrink from entry into the world war in early December 1941. His administration had adopted the objective of defeating all the Axis powers and had begun the military and the economic planning to achieve it. He had shared that objective publicly with the American people, a large majority of whom now accepted war as inevitable. In October, fully three-quarters of respondents to a Gallup poll said either that the United States would inevitably get into the war in Europe or that the United States was in the war already. Starkâ??s and Marshallâ??s last-minute memorandum suggested that the early months of the war might be perilous indeed, but the administrationâ??s Victory Program could not possibly be implemented in peacetime. With the Germans now halted before Moscow, ultimate victory over the Axis seemed at least possible, and the time to enter the war had come.

From Monday, December 1, through Thursday, December 4, new Magic intercepts conveyed Tokyoâ??s instructions to its diplomatic representatives in London, Singapore, Manila, Hong Kong, Washington, and various Chinese cities to destroy their codes and other publications. On December 6 in Tokyoâ??December 5 in the United Statesâ??the Foreign Ministry told the Embassy in Washington to await the delivery of a long message giving the Japanese reply to Hullâ??s November 26 note. War was obviously imminent. We must now look at both the manner in which the Japanese had decided to begin it, and the reasons why the key commanders in the Far East disregarded their warnings and so much available evidence and remained almost completely unprepared on the morning of December 7.