Despite the fact that the bulk of the navy was based in the Pacific, the initial deployment of U.S. naval forces in World War II was in the Atlantic theater and took place while the United States was still technically neutral. President Roosevelt aligned the United States with the European Allied powers, and following the fall of France, he sent material aid to Great Britain. The transport of these supplies across the Atlantic via merchant convoys led to the need to protect them against German submarines. By mid-1941, U.S. naval forces were engaged in escorting convoys to Iceland, where they then became Britain's responsibility. This situation led to an escalation of hostilities with the September 1941 German torpedo attack on the escorting destroyer Greer. Roosevelt responded with a "shoot on sight" order regarding Axis warships threatening convoys. On 31 October 1941, a German submarine torpedoed and sank the U.S. destroyer Reuben James, the first American warship lost in World War II.
Yet war for the United States came not in the Atlantic but in the Pacific. With the Japanese attack on Pearl Harbor, the nation formally joined the Allied side. The U.S. Navy, which by late December was under the direction of the commander in chief of the U.S. Fleet, Admiral Ernest J. King, faced a multiple-theater conflict. In the Atlantic, the war at sea centered on the protection of Allied supply lines to Great Britain. Although the Battle of the Atlantic was fought primarily by British and Canadian forces, the United States contributed through the deployment of convoy escorts largely under the direction of the Atlantic Fleet commander, Admiral Royal E. Ingersoll. In early 1943, the United States assumed responsibility for the protection of convoys in the Central Atlantic. In addition to the destroyer forces deployed for this duty, "hunter-killer groups" based around escort carriers executed search-and-destroy operations against Axis submarines. Through the use of radar and sonar, these forces played an important role in the Allied victory in the critical Battle of the Atlantic. By the close of the war, U.S. naval units had accounted for 25 percent of the 781 German U-boats sunk during the conflict.
In addition to commerce protection, the U.S. Navy also contributed warships to aid the Royal Navy in fleet surface operations in the Atlantic. In March 1942, the United States sent its first naval task force, centered on the aircraft carrier Wasp, into the Atlantic. The U.S. Navy provided critical gunfire support and sealift in all the Allied amphibious operations of the war, beginning with Operation torch, the Allied invasion of North Africa, and extending through Operation overlord, the Normandy Invasion. As with the U-boat war, the British provided the lion's share of the vessels required for this task.
Initial American involvement in the Mediterranean Theater was the result of Allied disagreement over the strategy to attack the European Axis powers. Although the United States favored an attack on German-held France via the English Channel, to take place in mid-1943, the prevailing British view called for a peripheral attack via the Mediterranean. This attack took the form of the November 1942 Operation torch, the amphibious invasion of North Africa. The Royal Navy conducted assaults on the Mediterranean beachheads of northern Africa, and the United States had responsibility for the Atlantic coast. The majority of the naval units covering the landing forces and providing fire support were British, and overall command of the naval force rested with the Royal Navy, but the U.S. Navy employed a task force under Rear Admiral H. Kent Hewitt that included 1 fleet carrier, 3 battleships, and 4 converted escort carriers. Following this operation, U.S. involvement increased through the mid-1943 Allied invasion of Sicily. Hewitt once again commanded an American squadron under the direction of the Royal Navy. This arrangement was repeated in the Allied invasion of mainland Italy.
In the June 1944 Normandy Invasion, of all the Allied gunfire support ships—7 battleships, 23 cruisers, and 80 destroyers—the United States supplied 3 battleships, 3 cruisers, and 31 destroyers. These vessels provided invaluable covering fire for amphibious forces landing on the beaches. The final major Allied landing in the Atlantic theater, Operation dragoon—the August 1944 invasion of southern France—was predominantly composed of U.S. units and under the command of Admiral Hewitt. The U.S. gunfire support ships included 3 battleships, 3 heavy cruisers, and numerous destroyers.
Although the involvement of the U.S. Navy in both the Atlantic and the Mediterranean was eclipsed by that of the Royal Navy, the chief reason for this was that the United States bore the brunt of the naval war in the Pacific. This effort faced great challenges from the outset, as the U.S. Pacific Fleet, under the command of Admiral Husband E. Kimmel, was gravely wounded by the Japanese attack on Pearl Harbor, which put all of the fleet's battleships out of commission. In any case, the initial American effort in the vast Pacific centered on U.S. Navy's carriers, which had not been in Pearl Harbor at the time of the attack. The denuded U.S. Pacific Fleet was further weakened following the loss of the British capital ships Prince of Wales and Repulse on 10 December 1941 and the February 1942 destruction of the American-British-Dutch-Australian (ABDA) Command, a collection of Allied warships. As a result of these blows, the U.S. Navy was, for most of the war, the sole Allied naval force pitted against the Japanese, who seized the U.S. possessions of Wake Island, Guam, and the Philippines.
Amid these disasters, U.S. and British military officials met in early 1942 and resolved that the United States would assume responsibility for the Pacific Theater. American strategists realized that, to defeat Japan, it was necessary to recapture lost American possessions and take Japanese Pacific holdings, thus isolating the Japanese home islands and starving their war machine of supplies. Command of the Pacific was divided into two theaters to achieve this end. The Southwest Pacific was under General Douglas MacArthur, who pursued an advance from Australia through the Netherlands East Indies to the Philippines. The North, Central, and South Pacific areas were assigned to Admiral Chester Nimitz, who succeeded Admiral Kimmel as commander of the U.S. Pacific Fleet. Consequently, Nimitz was in charge of the majority of U.S. naval forces in the Pacific. He pursued War Plan Orange, a prewar strategy that called for an advance toward Japan through the Central Pacific.
These operations, however, could not take place until the country's industrial strength produced more warships to augment the force that remained after Pearl Harbor. War Plan Orange saw the role of submarines as scouts for the U.S. battle line, but after the Japanese attack on Pearl Harbor, the U.S. Navy deployed its submarines with the destruction of Japanese overseas commerce as a key mission. Surface units were charged with preventing further Japanese expansion. While the submarine war unfolded, a critical concern was the threat posed to Australia, which was both a vital naval base and an area to station troops. The need to protect Australia led to the Battle of the Coral Sea in May 1942. This engagement aborted a Japanese landing at Port Moresby in New Guinea. A Japanese attempt to take Midway Island and draw out and destroy the U.S. carriers led to the pivotal Battle of Midway in June 1942. The loss of four of Japan's finest carriers in this battle was a great blow to further Japanese expansion in the Pacific and, in a very real sense, the turning point in the Pacific war.
The U.S. Navy subsequently implemented its plan to defeat Japan. The amphibious operations that ensued were made possible by the tremendous wartime naval production of the United States. By 1944, the U.S. Navy was larger than all other navies of the world combined, and the Pacific Fleet comprised 14 battleships, 15 fleet carriers, 10 escort carriers, 24 cruisers, and hundreds of destroyers and submarines. The Japanese, whose industrial base was much smaller than that of the United States, could not match this production.
One of the keys to Allied victory in the war was the ability of U.S. Navy task forces to operate at great distances across the vast Pacific. To support this effort, the navy created an extensive logistics network. This Service Force Pacific Fleet, known as the "fleet train," included tankers and supply and repair ships moving in the wake of the combat ships. A massive system of reprovisioning and repair, the fleet train markedly reduced the need for combat ships to spend precious time moving to and from their home bases and thus greatly increased the number of combat ships deployed.
In the Central Pacific, the navy lifted army and marine elements to take Japanese-held islands in the Marshall, Caroline, Mariana, and Philippine Islands. In the Battle of Leyte Gulf from 23 to 26 October 1944, the U.S. Navy eliminated the Imperial Japanese Navy (IJN) as a cohesive fighting force and cut the Japanese off from their southern resources area. The Allied conquest of Okinawa in mid-1945 signaled to American amphibious forces the completion of Plan Orange. With the destruction of the IJN and the seizure of bases within striking distance of Japan, the home islands were both isolated and subjected to the strategic bombing of cities and the devastation of coastal trade.
Equally important in the isolation of Japan was the submarine campaign, the most successful guerre de commerce (war against trade) in modern history. Of Japan's total of 8 million tons of merchant shipping (at best marginal for meeting Japanese requirements in peacetime), U.S. submarines sank almost 5 million tons, thus crippling Tokyo's ability to supply the home islands, especially with oil.
By the end of World War II, the U.S. Navy had participated in every major theater of the naval war. The cost was high, as the navy lost 36,674 officers and enlisted personnel. In the Battle of Okinawa alone, Japanese kamikaze attacks caused the navy more casualties than it had suffered in all its previous wars combined. Materially, the navy lost 2 battleships, 4 fleet aircraft carriers, 1 light carrier, 6 escort carriers, 12 cruisers, 68 destroyers, and 47 submarines in the course of the war. Nevertheless, the manpower and industrial strength of the United States had not only made good the losses but also augmented the navy to the point that its size in both personnel and ships eclipsed that of all the other naval powers of the world combined. This force was pivotal to the Allied victory in World War II. Eric W. Osborne
Blair, Clay. Silent Victory: The U.S. Submarine War against Japan. Philadelphia: Lippincott, 1975.; Howarth, Stephen. To Shining Sea: A History of the United States Navy, 1775–1998. Norman: University of Oklahoma Press, 1999.; Hoyt, Edwin. How They Won the War in the Pacific: Nimitz and His Admirals. New York: Weybright and Talley, 1970.; Miller, Nathan. The United States Navy: A History. Annapolis, MD: Naval Institute Press, 1997.; Morison, Samuel Eliot. History of U.S. Naval Operations in World War II. 15 vols. Boston: Little, Brown, 1947–1962.; Morison, Samuel Eliot. The Two-Ocean War: A Short History of the United States Navy in the Second World War. Boston: Little, Brown, 1963.; Muir, Malcolm, Jr. "The United States Navy." In James J. Sadkovich, ed., Reevaluating Major Naval Combatants of World War II, 1–17. New York: Greenwood Press, 1990.
Eric W. Osborne