Columbia subject headings:
National security--United States.
Terrorism--Government policy--United States.
Terrorism--United States--Prevention.
United States--Foreign relations.
Harvard subject headings:
National security--United States
Terrorism--Government policy--United States
Terrorism--United States--Prevention
United States--Foreign relations.
Princeton subject headings:
National security--United States.
Terrorism--Government policy--United States.
Terrorism--United States--Prevention.
United States--Foreign relations.