The bombing of Pearl Harbor on December 7, 1941, had major consequences for the United States, marking its entry into World War II. The surprise attack by the Japanese Navy resulted in significant loss of life and damage to the Pacific Fleet, galvanizing public opinion in favor of joining the conflict. It united the nation as Americans rallied to support the war effort, leading to profound shifts in military and industrial policies. The aftermath also paved the way for significant international alliances, such as the formation of NATO, and reshaped U.S. foreign policy for decades to come.