In one bold stroke, the United States had become fully involved in World War II. Uniting the nation behind the war effort, Pearl Harbor led Japanese Admiral Hara Tadaichi to later comment, "We won a great tactical victory at Pearl Harbor and thereby lost the war."
Amazing how little it did from a strategic sense to hamper American efforts and how completely it galvanized the country into one voice that said, "Enough with this #$@%."