The Lend-Lease program, initiated by the United States in March 1941 during World War II, signified an essential shift in American foreign policy. This program allowed the U.S. to supply Allied nations, particularly Britain and later the Soviet Union, with military equipment and supplies without direct payment. The Lend-Lease Act reflected an informal alliance against the Axis powers, demonstrating America's increasing involvement in the war before formally entering it after the attack on Pearl Harbor. It significantly bolstered Allied capabilities and laid the groundwork for post-war relations.