Final answer:
Franklin Delano Roosevelt served as the head of the U.S. Food Administration during WWI and played a key role in humanitarian efforts. His early presidency was marked by attempts to aid allied nations against totalitarianism, which evolved into the Lend-Lease Act. However, he vetoed a bill for early WWI veterans' bonus payments which Congress later passed.
Step-by-step explanation:
Franklin Delano Roosevelt's job during WWI was as the head of the U.S. Food Administration, appointed by President Woodrow Wilson. The aim was to coordinate the rationing efforts within the United States and secure essential food supplies for the Allied forces and European civilians. Before his presidency, FDR was already a key figure in humanitarian efforts, demonstrating skills that would later contribute to his leadership during the Great Depression and WWII. Early in his presidency, facing the rise of totalitarian regimes in Europe and Asia, Roosevelt took steps to aid nations struggling against this threat while respecting the U.S. sentiment of neutrality championed by the likes of Senator Gerald P. Nye.
These steps included a series of measures that culminated in the Lend-Lease Act, allowing the U.S. to provide military aid to foreign nations during WWII without direct involvement. In response to veterans of WWI seeking early bonus payments, Roosevelt vetoed the bill which Congress passed without his signature. His actions during WWI and prior to the U.S. entering WWII indicate his persistent focus on both domestic welfare and international stability.