When the Japanese attacked Pearl Harbor on December 7, 1941, the United States officially entered World War II. The Japanese government later learned that this single event triggered an explosion that then led the United States to attack the Midway Islands in the Pacific Ocean. Pearl Harbor was one of the largest naval bases in the United States and the largest in the Pacific Ocean. This attack ended all trade with Japan and officially added Japan as an enemy of the United States. The outbreak of a new world war created new concerns for the military. “World War II introduced a whole new set of problems to naval tactics” (Smith, 1). The main change driving these changes was the fact that aircraft carriers became more widespread and common in the naval forces of all major countries. Japan successfully attacked Pearl Harbor thanks to aircraft carriers launching their planes. Due to the battles preceding the Battle of Midway and the conflicts with Japan, it had a much greater impact on World War II as a whole and strengthened unity in America, leading to a period of more prosperous history after the war. The outcome of the Battle of Pearl Harbor did not meet Japan's ideals and retaliation was certain. Midway Island began preparing for battle: "After the somewhat shocking events of December 7, Midway, like Pearl Harbor, prepared for the worst with full anticipation that it would come" (Heinl , 16). Within two weeks, new shipments of American planes and troops had arrived on the island to stockpile resources. The United States was preparing to defend its fleet and the assets involved. The attack on Pearl Harbor opened Americans to the idea that the war had already begun, even as people knelt ... middle of paper ... to increase their supremacy as a country in the Pacific theater . Background to the Battle of Midway. Background to the Battle of Midway. Ohio State University, nd Web. April 25, 2014.Coale, Griffith Baily. Victory at Midway. New York: Farrar & Rinehart, 1944. Print. Fish, Bob. "Battle of Midway (CV-8)." USS Hornet. USS Hornet Museum, nd Web. April 25, 2014. Fuchida, Mitsuo and Masatake Okumiya. Midway, the battle that doomed Japan; The History of the Japanese Navy. Annapolis, Maryland: United States Naval Institute, 1955. Print.Heinl, Lieutenant Robert Debs, Jr. Marines at Midway. Washington: Historical Section, Public Information Division, Headquarters, US Marine Corps, 1948. Print.Lord, Walter. Incredible victory. New York: Harper & Row, 1967. Print. Smith, William Ward. Midway: a turning point in the Pacific. New York: Thomas Y. Crowell, 1966. Print.