Defining Terrorism: A Principled Approach

Can Terrorism Be Defined In A Principled Legal Fashion?

To solve a problem it must be defined. We will examine various legal definitions of terrorism, apply them to varying facts, and try to create our own.


I: Establish a common vocabulary

II: A brief history of "terrorism"

III: Law in wartime: Is it applicable?

IV: Examine current legal definitions

V: Why facts matter

VI: Create a definition

I: Establishing a Vocabulary


Armed Conflict

War Crime


Prisoner of War


A Definition of War

Measures Short of War

Severance of diplomatic relations




Display of force

Pacific blockade

Armed intervention without war

International organizational sanctions

A Definition of Armed Conflict

War Crime Defined

Some Examples of War Crimes

Grave Breaches of Geneva Conventions

Poisoned weapons

Treacherous requests for quarter

Misuse of Red Cross emblem


Improper use of privileged buildings

Violation of surrender terms

Some Other Relevant Crimes

A Definition of Belligerency

Prisoner of War Defined

Any belligerent person is entitled to treatment of as a POW, excluding 1) members of militias and volunteers not part of the armed forces who fail to meet the four part test; 2) other individuals who commit hostile acts; and 3) other individuals who commit war crimes. Spies are a special case.

Defining Terrorism: Some Factors to Consider

Use of violence

Identity of the target

Political motivation

Emphasis on instilling terror

Threats against targets

Systemic approach

Methods of attack

Identity of the perpetrator

Acts constituting war crimes

Terrorism: A General Definition

War crimes directed against civilians for political purposes by persons other than the regular armed forces of a lawful belligerent power.

II: A Brief History of Terrorism

Pre International Law





Soviet Bloc

1960s Revolutionaries

North Korea

Cuba, Nicaragua



III: Law Of War: Is it Applicable?

If, the nature of wars is inherently chaotic, and their conduct essentially criminal, what can be the purposes and uses of a legal regime? We can posit several.

Law of War Provides Rational Analysis

It is axiomatic that a subject which can not be articulated cannot be analyzed or regulated. Rational analysis of existing practices must precede any attempt to limit their impact. Legal norms lend themselves to such analysis.

Law of War Provides Structure

While criminal sanctions in any regime may not deter certain willing violators, they do provide guidance and structure for participants concerned with community opinion. On a global stage that concern and those opinions may be national or individual, but they have, in either case, often impacted behavior in wartime.

Law of War Promotes Basic Rights

There is a legitimate concern with limiting suffering, and in safeguarding fundamental human rights, among both combatants and noncombatants on all sides in any potential conflict. Short of government by anarchy, most nation states have an inherent interest in at least the basic welfare of their population.

Law of War Often Effectively Bans Weapons

The use or possession of certain weapons or engagement in certain practices may be so disproportionably destructive that they are generally banned by all potential contestants. Such bans have been surprisingly effective among combatants in even the fiercest hostilities.

Law of War Gives Predictability to Enemy Occupation

A regime establishing legal rights and duties of the possessor and inhabitants of enemy occupied territory has the same virtues as any other system of government. While it may not be popular or democratic, it at least provides that temporary framework of stability so necessary to civil life.

Law of War Promotes Peacemaking

During and following active hostilities constraints on warfare facilitate contacts between enemies and peacemaking activities. It is simply easier to negotiate with an opponent which is perceived as an adherent of international law.

IV: Current Legal Definitions of Terrorism

International Definitions

State Definitions

Academic Definition

Treaty Definitions of Terrorism

League of Nations Convention

U.N. General Assembly Res. 51/210

Convention for Suppression of Terrorist Bombings

Convention for Suppression of Financing of Terrorism

European Union Council Framework Decision

League of Nations Convention 1937

All criminal acts directed against a State and intended or calculated to create a state of terror in the minds of particular persons or a group of persons or the general public.

G.A. Resolution 51/210 1999

Reiterates that criminal acts intended or calculated to provoke a state of terror in the general public, a group of persons or particular persons for political purposes are in any circumstances unjustified, whatever the considerations of a political, philosophical, ideological, racial, ethnic, religious or other nature that may be invoked to justify them.

Convention for Suppression of Terrorist Bombings

1. Any person commits an offence within the meaning of this Convention if that person unlawfully and intentionally delivers, places, discharges or detonates an explosive or other lethal device in, into or against a place of public use, a State or government facility, a public transportation system or an infrastructure facility:

(a) With the intent to cause death or serious bodily injury; or

(b) With the intent to cause extensive destruction of such a place, facility or system, where such destruction results in or is likely to result in major economic loss.

Article 2

Convention for Suppression of the Financing of Terrorism

1. Any person commits an offence within the meaning of this Convention if that person by any means, directly or indirectly, unlawfully and willfully, provides or collects funds with the intention that they should be used or in the knowledge that they are to be used, in full or in part, in order to carry out:

(a) An act which constitutes an offence within the scope of and as defined in one of the treaties listed in the Annex; or

(b) Any other act intended to cause death or serious bodily injury to a civilian, or to any other person not taking an active part in the hostilities in a situation of armed conflict, when the purpose of such act, by its nature or context, is to intimidate a population, or to compel a government or an international organization to do or to abstain from doing any act. Article 2

European Union Council Framework Decision

Each Member State shall take the necessary measures to ensure that the following offenses, defined according to its national law, which are intentionally committed by an individual or a group against one or more countries, their institutions or people with the aim of intimidating them or seriously altering or destroying the political, economic or social structures of a country, will be punishable as terrorist offenses: murder; bodily injuries; kidnapping or hostage taking; extortion; theft or robbery, unlawful seizure or or damage to [property]; fabrication [obtaining or supplying] weapons or explosives; releasing contaminating substances…; interfering with the supply of water, [or] power…; attacks through interference with an information system…

State Definitions of Terrorism

Examples of National Definitions

United States


United Kingdom

United States

The term "international terrorism" means activities that--

(A) involve violent acts or acts dangerous to human life that are a violation of the criminal laws of the United States or of any State, or that would be a criminal violation if committed within the jurisdiction of the United States or of any State;

(B) appear to be intended--

(i) to intimidate or coerce a civilian population;

(ii) to influence the policy of a government by intimidation or coercion; or

(iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping; and

(C) occur primarily outside the territorial jurisdiction of the United States, or transcend national boundaries in terms of the means by which they are accomplished, the persons they appear intended to intimidate or coerce, or the locale in which their perpetrators operate or seek asylum

18 U.S.C.A. § 2331


Terrorist Activity: An action that takes place within or outside Canada that:

-Is an offense under one of the ten U.N. anti-terrorism conventions and protocols; or

-Is taken or threatened for political, religious or ideological purposes and threatens the public or national security by killing, seriously harming or endangering a person, causing substantial property damage that is likely to seriously harm people or by interfering with or disrupting an essential service, facility or system.

United Kingdom

Terrorism means the use or threat of action where-…

(b) the use or threat is designed to influence the government or to intimidate the public or a section of the public, and

(c) the use or threat is made for the purpose of advancing a political, religious or ideological cause.

(2) Action falls within this subsection if it-

(a) involves serious violence against a person,

(b) involves serious damage to property,

(c) endangers a person's life, other than that of the person committing the action,

(d) creates a serious risk to the health or safety of the public or a section of the public, or

(e) is designed seriously to interfere with or seriously to disrupt an electronic system.

(3) The use or threat of action falling within subsection (2) which involves the use of firearms or explosives is terrorism whether or not subsection (1)(b) is satisfied.

An Academic Definition

Terrorism is an anxiety inspiring method of repeated violent action, employed by clandestine individual, group or state actors for idiosyncratic, criminal or political reasons, where by-in contrast to assassination-the direct targets are not the main targets. The immediate human victims…are generally chosen randomly or selectively from a target population and serve as message generators. Threat communication processes between terrorist victims and main targets are used to manipulate the main target.

Schmid & Jongman, Political Terrorism (1988)

V: Why Facts Matter

Status must be determined on a case by case basis

Distinctions include:

Terrorist vs. Soldier

Prisoner of War vs. Enemy Combatant

State vs. Terrorist Organization

War criminal vs. legitimate fighter

Courts are uniquely qualified to determine disputed facts

VI: Creating A Definition

What factors have we identified?

What makes a definition workable?

An exercise in legislative drafting

Some Factors Of Terrorism

Use of violence

Identity of the target

Political motivation

Emphasis on instilling terror

Threats against targets

Systemic approach

Methods of attack

Identity of the perpetrator

Acts constituting war crimes

What Makes It Workable?




Limits on Abuse

Constitutional Requirements

Treaty Requirements

Imminence and Potential of the Threat

Other Factors?

Legislative Drafting Exercise

How do we balance all the interests which have been identified in this session?

The Nicaragua/US Example

Drafting A Statute

Applying the draft law to the facts


I: Established a common vocabulary

II: Discussed history of "terrorism"

III: Discussed law in wartime applicable

IV: Discussed current legal definitions

V: Discussed why facts matter

VI: Created a definition

What Have We Learned?


Where to Get More Information


Schmid & Jongman, Political Terrorism (1988)

Bassiouni, International Terrorism Multilateral Conventions (2001)