Columbia subject headings:
Communism--United States.
Internal security--United States--History--20th century.
United States--Foreign relations--1945-1953.
United States--Politics and government--1945-1953.
Harvard subject headings:
Communism--United States
Communism--United States--1917-
Internal security--United States--History--20th century
United States--Foreign relations--1945-1953.
United States--Politics and government--1945-1953.
Princeton subject headings:
Communism--United States.
Internal security--United States--History--20th century.
United States--Foreign relations--1945-1953.
United States--Politics and government--1945-1953.