On July 19, 1940, the US passed the Vinson-Walsh Act, better known as the Two-Ocean Navy Act, which immediately increased the size of the US Navy by 70 percent.
Although a few small naval construction bills had made it through an isolationist US Congress during the 1930s, it took the Germans overrunning France in six weeks and the Japanese threatening American possessions across the Pacific to get the government to react. There were real concerns the Americans would have to fight both at the same time, and possibly alone, if the Allies were defeated before the United States entered the war. During the period leading up to the Japanese strike at Pearl Harbor in December 1941, the US Navy was racing to build a fleet capable of taking on the Germans in the Atlantic and the Japanese in the Pacific.
