The Attack on Pearl Harbor and World War II “I fear all we have done is wake a sleeping giant” (Pierce 43) . This is exactly what the Japanese did: awaken a “sleeping giant”. The United States has long tried to stay out of World War II. Finally, when the Japanese attacked Pearl Harbor, the United States had no choice but to enter the war. The attack on Pearl Harbor on December 7, 1941, greatly affected the United States and also changed the course of subsequent events in American history. Admiral Yamamoto said, “A brilliant man will find a way not to go to war” (23). . Most countries don't attack another country without good reason. The Japanese reason for the attack was to dominate all of Southeast Asia, the Pacific Islands, China, and Australia (Remembering Pearl Harbor 2). In the 1880s and 1890s, Japan began spending more money to invest in a stronger military and nation (Pierce 10).