What was the name of the US law that allowed arms sales to Britain in 1941?

The US law that allowed arms sales and transfers to Britain in 1941 was the Lend-Lease Act. Signed by President Franklin D. Roosevelt on 11 March 1941, the law let the United States supply countries whose defense was considered vital to American security.

Britain was the first and most important early beneficiary. By 1941, Britain was fighting Germany largely on its own in Europe and urgently needed aircraft, ships, vehicles, food, fuel, and ammunition. Lend-Lease allowed Washington to provide this material without requiring immediate cash payment, replacing the older “cash-and-carry” system.

The program soon expanded beyond Britain. The United States supplied the Soviet Union after Germany invaded it in June 1941, as well as China and other Allied nations. American factories and shipping therefore became a major source of Allied military strength before and after the United States entered the war in December 1941.

Lend-Lease was not the Marshall Plan, which rebuilt Europe after the war. It was also distinct from the Atlantic Charter and from earlier Neutrality Acts that restricted American involvement.