Early in 1938, Roosevelt proposed a 20 percent increase in U.S. warship tonnage, an increase that Congress approved on 17 May. Through the remainder of 1938 and into 1939, as Germany's aggressive moves led to the absorption of Czechoslovakia and prompted Anglo-French guarantees of Poland's security, Roosevelt concluded that the greater danger to U.S. national interests lay in the Atlantic rather than the Pacific, with a special concern for defending the Panama Canal. After World War II began in September 1939, Roosevelt organized a "neutrality patrol" in the western Atlantic, defined in October 1939 as lying west of a line from the Saint Lawrence River to Trinidad.
German conquest of the Low Countries and France in May and June 1940 affected the Pacific as well as the Atlantic. French possessions in Indochina and Dutch holdings in the Netherlands East Indies were tempting targets for the Japanese, as were the Philippines. On 14 June 1940, as he was still planning a defensive posture in the Pacific while making the Atlantic the main theater of American naval operations, Roosevelt requested a 25 percent increase in the carrier, cruiser, and submarine tonnage authorized in May 1938, amounting to an 11 percent rise in total U.S. fleet tonnage. Three days later, after German troops had occupied Paris, Chief of Naval Operations Admiral Harold Stark asked Congress to appropriate $4 billion for a two-ocean navy—a 70 percent increase in the combat fleet, which would add 1,325,000 tons of new construction, amounting to 257 ships above the 488 that already existed or were being built at that time.
Roosevelt signed the Two-Ocean Navy Act on 19 July 1940. The largest naval appropriation in U.S. history and designed to increase the size of the navy by 70 percent, it authorized construction of 2 new Iowa-class and 5 Montana-class battleships, 6 Alaska-class battle cruisers, 18 aircraft carriers, 27 cruisers, 115 destroyers, 43 submarines, and 15,000 aircraft. It also provided for the purchase or conversion of 100,000 tons of auxiliary ships and the expenditure of $50 million for patrol, escort, and miscellaneous vessels. Although modified to meet the changing demands of the war, the act created the combat core of the U.S. Navy as it developed from the middle of 1942 through the remainder of the war and for much of the decade that followed. Under its aegis were built the Essex-class carriers, Baltimore-class heavy cruisers, Cleveland- and Atlanta-class light cruisers, Bristol- and Fletcher-class destroyers, and numerous submarines and smaller surface vessels.
John A. Hutcheson Jr.
Abbazia, Patrick. Mr. Roosevelt's Navy: The Private War of the Atlantic Fleet, 1939–1942. Annapolis, MD: Naval Institute Press, 1975.; Hagan, Kenneth J. This People's Navy: The Making of American Sea Power. New York: Free Press, 1991.; Morison, Samuel Eliot. History of United States Naval Operations in World War II. Vol. 5, The Struggle for Guadalcanal, August 1942–February 1943. Boston: Little, Brown, 1949.