Columbia subject headings:
Harvard subject headings:
September 11 Terrorist Attacks, 2001--Influence
September 11 Terrorist Attacks, 2001--Political aspects.
United States--Foreign relations--21st century.
World politics--21st century
Princeton subject headings:
September 11 Terrorist Attacks, 2001--Influence.
September 11 Terrorist Attacks, 2001--Political aspects.
United States--Foreign relations--21st century.
World politics--21st century.