terrorism, the threat or use of violence, often against the civilian population, to achieve political or social ends, to intimidate opponents, or to publicize grievances. The term dates from the Reign of Terror (1793–94) in the French Revolution but has taken on additional meaning in the 20th cent. Terrorism involves activities such as assassinations, bombings, random killings, and hijackings. Used for political, not military, purposes, and most typically by groups too weak to mount open assaults, it is a modern tool of the alienated, and its psychological impact on the public has increased because of extensive coverage by the media. Political terrorism also may be part of a government campaign to eliminate the opposition, as under Hitler, Mussolini, Stalin, and others, or may be part of a revolutionary effort to overthrow a regime. Terrorist attacks also are now a common tactic in guerrilla warfare. Governments find attacks by terrorist groups difficult to prevent; international agreements to tighten borders or return terrorists for trial may offer some deterrence.

Terrorism reaches back to ancient Greece and has occurred throughout history. Terrorism by radicals (of both the left and right) and by nationalists became widespread after World War II. Since the late 20th cent. acts of terrorism have been associated with the Italian Red Brigades, the Irish Republican Army, the Palestine Liberation Organization, Peru's Shining Path, Sri Lanka's Liberation Tigers of Tamil Eelam, the Weathermen and some members of U.S. "militia" organizations, among many groups. Religiously inspired terrrorism has also occurred, such as that of extremist Christian opponents of abortion in the United States; of extremist Muslims associated with Hamas, Osama bin Laden's Al Qaeda, and other organizations; of extremist Sikhs in India; and of Japan's Aum Shinrikyo, who released nerve gas in Tokyo's subway system (1995).

In 1999 the UN Security Council unanimously called for better international cooperation in fighting terrorism and asked governments not to aid terrorists. The Sept. 11, 2001, attacks by Al Qaeda on the World Trade Center and the Pentagon—the most devastating terrorist attacks in history—prompted calls by U.S. political leaders for a world "war on terrorism." Although the U.S. effort to destroy Al Qaeda and overthrow the Afghani government that hosted it was initially successful, terrorism is not a movement but a tactic used by a wide variety of groups, some of which are regarded (and supported) as "freedom fighters" in various countries or by various peoples. So-called state-sponsored terrorism, in which governments provide support or protection to terrorist groups that carry out proxy attacks against other countries, also complicates international efforts to end terror attacks, but financial sanctions have been placed by many countries on organizations that directly or indirectly support terrorists. The 2001 bioterror attacks in which anthrax spores were mailed to various U.S. media and government offices may not be linked to the events of September 11, but they raised specter of biological and chemical terrorism and revealed the difficulty of dealing with such attacks.

See B. Hoffman, Inside Terrorism (1998); M. Carr, The Infernal Machine: A History of Terrorism (2007); S. Nathanson, Terrorism and the Ethics of War (2010); M. A. Miller, The Foundations of Modern Terrorism (2013).

The Columbia Encyclopedia, 6th ed. Copyright© 2013, The Columbia University Press.

Selected full-text books and articles on this topic

The Rhetoric of Terrorism and Counterterrorism
Richard W. Leeman.
Greenwood Press, 1991
Terrorism, Counterterrorism and International Law
Weiss, Peter Ulrich.
Arab Studies Quarterly (ASQ), Spring-Summer 2002
Phoenix and the Birds of Prey: Counterinsurgency and Counterterrorism in Vietnam
Mark Moyar.
University of Nebraska Press, 2007
A High Price: The Triumphs and Failures of Israeli Counterterrorism
Daniel Byman.
Oxford University Press, 2011
Quick Scan of Post 9/11 National Counter-Terrorism Policymaking and Implementation in Selected European Countries: Research Project for the Netherlands Ministry of Justice
Erik Van De Linde; Kevin Oíbrien; Gustav Lindstrom; Stephan De Spiegeleire; Mikko Vayrynen; Han De Vries.
Rand, 2002
Confronting "The Enemy Within": Security Intelligence, the Police, and Counterterrorism in Four Democracies
Peter Chalk; William Rosenau.
Rand, 2004
Countering the New Terrorism
Ian O. Lesser; Bruce Hoffman; John Arquilla; David Ronfeldt; Michele Zanini.
Rand, 1999
Terrorists and Terrorism in the Contemporary World
David J. Whittaker.
Routledge, 2004
Librarian’s tip: Chap. 10 "Countering Terrorists"
Global Terrorism
James M. Lutz; Brenda J. Lutz.
Routledge, 2004
Librarian’s tip: Chap. 12 "Counterterrorism"
Fear and the Regulatory Model of Counterterrorism
Posner, Eric A.
Harvard Journal of Law & Public Policy, Vol. 25, No. 2, Spring 2002
Hijacking and Hostages: Government Responses to Terrorism
J. Paul De B. Taillon.
Praeger, 2002
Librarian’s tip: Chap. 2 "International Aspects of Counterterrorism"
The Evolution of Special Forces in Counter-Terrorism: The British and American Experiences
J. Paul De B. Taillon.
Praeger, 2001
The Merging of the Counter-Terrorism and Anti-Money Laundering Regimes
Zagaris, Bruce.
Law and Policy in International Business, Vol. 34, No. 1, Fall 2002
Deterrence and Influence in Counterterrorism: A Component in the War on al Qaeda
Paul K. Davis; Brian Michael Jenkins.
Rand, 2002
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