Two interesting articles on the run-up to the Pacific War.
The key lesson for today is to recognize that a policy can be morally right but strategically obtuse.
Japan's Decision for War in 1941: Some Enduring Lessons
Still, it cannot be denied that, in threatening Japan's economic destruction (and consequent military impoverishment), the United States placed the Japanese in a position in which the only choices open to them were war or subservience. "Never inflict upon another major military power a policy which would cause you yourself to go to war unless you are fully prepared to engage that power militarily," cautions Roland Worth, Jr., in his No Choice But War: The United States Embargo against Japan and the Eruption of War in the Pacific. "And don't be surprised that if they do decide to retaliate, that they seek out a time and a place that inflicts maximum harm and humiliation upon your cause."
The U.S. insistence, after Japanese forces moved into southern Indochina, that Japan evacuate China as well as Indochina, as a condition for the restoration of trade relations, thus made no sense as a means of dissuading the Japanese from moving south. On the contrary, the demand that Japan quit China killed any prospect of a negotiated alternative to Japan's conquest of Southeast Asia (e.g., restored trade in exchange for Japan's withdrawal from Indochina). In effect, the United States went to war over China rather than Southeast Asia -- a volte-face of enormous strategic consequence since it propelled the United States into a war with Japan over a remote country for which the United States had never been prepared to fight. The fate of China, even of Southeast Asia, did not engage core U.S. security interests, especially at a time when Europe's fate hung in the balance. A war with Japan was, of course, a war the United States was always going to win, but Japan was not the enemy the Roosevelt administration wanted to fight. The United States could have settled its accounts with Japan after Hitler's defeat had been assured. Was denying Japan an expanded empire in Southeast Asia more important, in 1941, than defeating Hitler?