The Japanese decision to initiate war against the United States in 1941 continues to perplex. Did the Japanese recognize the odds against them? How did they expect to defeat the United States? The presumption of irrationality is natural, given Japan's acute imperial overstretch in 1941 and America's overwhelming industrial might and latent military power. The Japanese decision for war, however, must be seen in the light of the available alternatives in the fall of 1941, which were either national economic suffocation or surrender of Tokyo's empire on the Asian mainland. Though Japanese aggression in East Asia was the root cause of the Pacific War, the road to Pearl Harbor was built on American as well as Japanese miscalculations, most of them mired in mutual cultural ignorance and racial arrogance. Japan's aggression in China, military alliance with Hitler, and proclamation of a "Greater East Asian Co-Prosperity Sphere" that included resource-rich Southeast Asia were major milestones along the road to war, but the proximate cause was Japan's occupation of southern French Indochina in July 1941, which placed Japanese forces in a position to grab Malaya, Singapore, and the Dutch East Indies. Japan's threatened conquest of Southeast Asia, which in turn would threaten Great Britain's ability to resist Nazi aggression in Europe, prompted the administration of Franklin D. Roosevelt to sanction Japan by imposing an embargo on U.S. oil exports upon which the Japanese economy was critically dependent. Yet the embargo, far from deterring further Japanese aggression, prompted a Tokyo decision to invade Southeast Asia. By mid-1941 Japanese leaders believed that war with the United States was inevitable and that it was imperative to seize the Dutch East Indies, which offered a substitute for dependency on American oil. The attack on Pearl Harbor was essentially a flanking raid in support of the main event, which was the conquest of Malaya, Singapore, the Indies, and the Philippines, Japan's decision for war rested on several assumptions, some realistic, others not. The first was that time was working against Japan-i.e., the longer they took to initiate war with the United States, the dimmer its prospects for success. The Japanese also assumed they had little chance of winning a protracted war with the United States but hoped they could force the Americans into a murderous, island-by-island slog across the Central and Southwestern Pacific that would eventually exhaust American will to fight on to total victory. The Japanese believed they were racially and spiritually superior to the Americans, whom they regarded as an effete, creature-comforted people divided by political factionalism and racial and class strife. U.S. attempts to deter Japanese expansion into the Southwestern Pacific via the imposition of harsh economic sanctions, redeployment of the U.S. Fleet from southern California to Pearl Harbor, and the dispatch of B-17 long-range bombers to the Philippines all failed because the United States insisted that Japan evacuate both Indochina and China as the price for a restoration of U.S. trade. The United States demanded, in effect, that Japan abandon its empire, and by extension its aspiration to become a great power, and submit to the economic dominion of the United States-something no self-respecting Japanese leader could accept.