Columbia subject headings:
Harvard subject headings:
Polarization (Social sciences)
September 11 Terrorist Attacks, 2001
United States--Foreign relations--2001-2009.
United States--Politics and government--2001-2009
War on Terrorism, 2001-2009
World politics--21st century
Princeton subject headings:
Terrorism--Religious aspects--Islam.
United States--Foreign relations--2001-2009.
War on Terrorism, 2001-2009.