Columbia subject headings:
United States--Civilization--1865-1918.
United States--Civilization--20th century.
United States--Politics and government--1865-1900.
United States--Politics and government--20th century.
Harvard subject headings:
United States--Civilization--20th century.
United States--History--20th century.
United States--Politics and government--20th century.
Princeton subject headings:
United States--History--20th century.
United States--Politics and government--20th century.