Japan attacked Pearl Harbor primarily due to its need for natural resources, especially oil, which was cut off by U.S. economic sanctions and embargoes in response to Japan's aggressive expansion in Asia. Japan aimed to establish dominance in the Asia-Pacific region under the Greater East Asia Co-Prosperity Sphere and saw the U.S. Pacific Fleet at Pearl Harbor as a major obstacle to its expansion ambitions. The attack was intended as a pre-emptive strike to cripple the U.S. naval power and prevent American interference while Japan secured resource-rich territories in Southeast Asia. Additionally, diplomatic negotiations had broken down, and Japan felt cornered by U.S. demands to withdraw from occupied territories. Japan's military leaders hoped the surprise attack would demoralize the U.S. and force it into negotiation, although this miscalculation ultimately led to America's full entry into World War II.
