Columbia subject headings:
Internal security--Europe--Congresses.
Internal security--United States--Congresses.
National security--Europe--Congresses.
National security--United States--Congresses.
September 11 Terrorist Attacks, 2001--Influence--Congresses.
Terrorism--Prevention.
United States. Department of Homeland Security.
Harvard subject headings:
Internal security--Europe--Congresses.
Internal security--United States--Congresses.
National security--Europe--Congresses
National security--United States--Congresses
September 11 Terrorist Attacks, 2001--Influence--Congresses.
Terrorism--Prevention--Congresses
United States. Department of Homeland Security.
Princeton subject headings: