In the 1930s, as a reply to the increasing agitation in Europe and Asia that would eventually lead to World War II, the United States Congress passed the Neutrality Acts. These were impelled by the growing isolationism and non-interventionism policy that followed the expensive involvement in World War I and aimed to guarantee that the country would not become compromised over foreign conflicts again.
In 1941 the Neutrality Acts were widely repealed. The Lend-Lease policy aimed to defeat Germany, Japan, and Italy by distributing supplies between 1941 and 1945 put an end to the United States' pretense of neutrality.