The President of the United States had a strategic dilemma throughout the start of World War II. President Franklin Delano Roosevelt was secretly aiding the British in their war against Nazi Germany. He did not want war with Japan, because it would prevent the full weight of the United States military and industry from being brought to bear on Germany. He felt that the China Incident -as the Second Sino-Japanese War was known in the late 1930's - was diverting the attention away from the more important threat in Europe.
The American public did not share his sense of urgency. The European War seemed far away. The American public blamed the Europeans for their war. China, while forgotten during the invasion of Poland, the Fall of France, and the Battle of Britain, seemed to most Americans to be the war America should fight, if America had to fight at all.
The heady days of December 7-10, 1941, with the Japanese advancing successfully along the entire front, must have been sorely trying on Roosevelt. The American public was incensed by the bombing of Pearl Harbor, which was seen as a treacherous, even cowardly, first strike against an unprepared America. While Roosevelt would be forever accused of allowing the attack to happen, in December 1941 the American public united against Japan in a way that the week before seemed impossible.
For Roosevelt, it was the wrong war at the wrong time. While Churchill reveled in the American entry into the war, saying "so we had won after all," he was making an assumption that most Americans were not - that the United States would be fighting against Germany. If in 1941, Roosevelt had gone to Congress with a declaration of war against Germany when the Japanese were winning everywhere, he would have lost crucial congressional support, perhaps even hounded out of office.