| 1903 | Department of Labor and Commerce established to promote fair business practices |
| 1906 | Pure Food and Drug Act |
| Meat Inspection Act; Hepburn Act | |
| 1910 | White Slave Trade Act |
| 1913 | Underwood Act reduces tariffs to benefit farmers |
| Sixteenth Amendment (graduated income tax) | |
| Seventeenth Amendment (election of senators by popular vote) | |
| Federal Reserve System | |
| 1914 | Harrison Narcotics Control Act |
| Federal Trade Commission | |
| Clayton Antitrust Act | |
| 1916 | Adamson Act provides eight-hour workday for railroad workers |
| Keating-Owen Act outlaws child labor in firms engaged in interstate commerce | |
| Workmen’s Compensation Act | |
| 1919 | Eighteenth Amendment (prohibition) |
| 1920 | Nineteenth Amendment (women’s suffrage) |