At the start of World War II, the United States wanted to remain neutral. American laws passed in the 1930s were meant to ensure that the US did not get entangled in another foreign war the way it had in WWI. However, President Roosevelt felt that Germany was a major threat to US interests and was gradually moving the US towards greater involvement. He did this through such things as the "destroyers for bases" deal with England. In time, he was able to persuade Congress to pass the Lend-Lease Act in which the US started to send supplies to the Allies. By doing things like this, Roosevelt was able to get the US more involved in the war while remaining officially neutral.
As World War II approached, the United States responded to totalitarian aggression while staying neutral. There were several actions that we took. In 1937, President Roosevelt warned Americans of the impending danger when he gave his “Quarantine Speech.” He wanted Americans to be aware that conditions around the world were deteriorating.
Another action we took was to alter the neutrality laws. In 1939, we allowed the sale of war materials to nations if they paid cash for the items and transported the products themselves. This favored Great Britain.
More actions also occurred. In 1940, Roosevelt began the Destroyers for Bases program. We gave Britain destroyers, and they let us build bases in British-controlled lands. In 1941, the Lend Lease Act was based. This allowed us to lend or lease war materials to the British. We also created a hemispheric defense zone. This allowed us to patrol the western Atlantic. We could help the British by warning them where German submarines were located.
There were actions we took against Japan also. The Export Control Act allowed us to limit the sale of important war materials to other countries. We stopped selling Japan oil and scrap metal. We also froze Japanese financial assets in our banks. There were various actions we took against the totalitarian countries while remaining neutral.
The United States was initially a neutral party to World War II due to the passage of the Neutrality Acts of the 1930s, enacted to ensure that the US was not dragged into another costly war like World War I. The acts treated both the attacker and victim as belligerent parties and decided to halt shipments of supplies to both of them. However, with growing turmoil in Europe and Asia, the US decided to intervene while maintaining neutrality. In November 1939, the Neutrality Acts were modified to allow "Cash and Carry" purchases by the allied countries; this allowed material and arms export to Britain, France and China. Further, President Roosevelt ordered an embargo on Japan, while not including the US in direct war. Finally, after the repeated attacks by German submarines on US ships and Japan's attack on Pearl Harbor, the US was forced into the war.