| 1903 | Department of Labor and Commerce established to promote fair business practices Elkins Act |
| 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) |