What was the prevailing economic challenge the United States faced at the start of World War II?

The greatest challenge of the United States during World War II is the filing of military supply orders. They suffered lack of resource support in their fighting forces. And this reason gave them a challenge on how to win the war. So they decided to mobilize their resource, this mobilization includes training of their personnel and production of their weapons and equipment. This industrial mobilization of resources gave them a bigger chance to attain victory in the World War II.