The pivotal event that the Lend-Lease Act of 1941 reflected regarding U.S. assistance during World War II was the U.S. commitment to support the Allied powers before formally entering the war. By allowing the transfer of military supplies to countries such as Britain and China, the act represented a significant shift in American foreign policy from isolationism to active support of nations resisting Axis aggression. This legislation not only bolstered allied forces but also laid the groundwork for the U.S. military mobilization that followed after the attack on Pearl Harbor.