Lend-Lease, formally the Lend-Lease Act and introduced as An Act to Promote the Defense of the United States, was a policy under which the United States supplied the United Kingdom, the Soviet Union, France, the Republic of China, and other Allied nations of the Second World War with food, oil, and materiel between 1941 and 1945. The aid was given free of charge on the basis that such help was essential for the defense of the United States.