Final answer:
Before WWII, the U.S. military was not ranked second in the world but rather emerged as a military superpower after the conflict, which is false in relation to the provided question.
Step-by-step explanation:
The statement that the U.S. military was ranked second in the world before WWII is false. Prior to World War II, particularly during the interwar period after World War I and before World War II, the United States mostly embraced an isolationist stance, and its military was not ranked within the top few in the world. In fact, in 1917 when the United States declared war on Germany during World War I, the U.S. Army was ranked seventh in the world.
However, by the end of World War II, the United States had emerged as a military and economic powerhouse, having avoided the level of destruction experienced in Europe and Asia, and having provided an arsenal for the Allied powers through the leadership of President Roosevelt. American factories produced a significant portion of the world's armaments, and the country experienced a surge in economic prosperity.