Louis Rene Beres


Department of Political Science

Purdue University

LAEB Building

West Lafayette IN 47907


TEL 765 494-4189

FAX 765 494-0833



It is regrettable that despite the increasingly large volume of publications dealing with terrorism, little if any serious progress has been made in suitably clarifying that concept, in distinguishing it clearly from various other uses of force in world politics and from other related crimes under international law. Indeed, judging from the standard definitions of terrorism now in "professional" use, definitions that offer no operational benefit for scholars or practitioners, the term has become so broad and so imprecise that it embraces even the most discrepant and opposing activities. For example, using certain of the prevailing definitions of terrorism adopted by some U.S. Government agencies and some scholars, the American Revolution, the Gulf War (Desert Storm), the contra insurgency in Nicaragua, and the anti-Castro insurgency supported by the United States were/are all examples of "terrorism."

Typical of these official and unofficial definitions are the following:

"...the unlawful use or threatened use of force or violence by a revolutionary organization against individuals or property with the intention of coercing or intimidating governments or societies, often for political or ideological purposes."

Department of Defense

"...the unlawful use of force or violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives."


"...premeditated, politically motivated violence perpetrated against noncombatant targets by subnational groups or clandestine state agents."

Department of State

"...violent criminal conduct apparently intended: (a) to intimidate or coerce a civilian population; (b) to influence the conduct of a government by intimidation or coercion; or (c) to affect the conduct of a government by assassination or kidnapping."

Department of Justice

"...the unlawful use or threat of violence against persons or property to further political or social objectives. It is usually intended to intimidate or coerce a government, individuals or groups or to modify their behavior or policies."

The Vice-President's Task Force on Combatting Terrorism (1986)

"Terrorism is the deliberate employment of violence or the threat of the use of violence by subnational groups and sovereign states to attain strategic and political objectives. Terrorists seek to create overwhelming fear in a target population larger than the civilian or military victims attacked or threatened. Acts of individual and collective terrorism committed in modern times have introduced a new breed of extralegal "warfare" in terms of threats, technology, targets, and impact."

Yonah Alexander, MIDDLE EAST TERRORISM (1994)

What, exactly, is wrong with these definitions? First, although a few do attempt to demarcate between lawful and unlawful uses of force, it is left entirely to the reader to determine which particular criteria of legality should be applied. Are the references to national law criteria? Are they to international law criteria? Do they refer to both criteria of jurisprudential assessment? And what, for that matter, authoritatively constitutes pertinent criteria under national and international law?

Second, those definitions of terrorism making no explicit reference to legality also omit the essential elements of "just cause" (jus ad bellum) and "just means" (jus in bello). These indispensable elements distinguish permissible from impermissible insurgencies under international law. Moreover, in view of the supremacy of certain international law over national or domestic law and of its pertinent incorporation, these elements are relevant whichever realm of law or combination of realms is implicitly under consideration. Lacking these elements, a definition of terrorism necessarily includes both permissible and impermissible forms of insurgency. Hence, it is an altogether useless definition.

Third, those definitions referencing "threatened use of force or violence" or "threat of violence" never establish needed and identifiable thresholds of threat. When, exactly, is the threat sufficient to argue convincingly for the presence of terrorism? In the absence of settled, unambiguous thresholds, inclusion of "threat" within the definition can serve only propagandistic and/or geopolitical purposes.

Fourth, those definitions that do not specify insurgent organizations exclusively broaden the meaning of terrorism to unmanageable and operationally useless levels. As a crime under international law, terrorism cannot be committed by states. This is a most sensible exclusion because the alternative would lead to unwieldy conceptual expansion, "blending" with other related crimes (e.g., aggression ) and a consequent watering-down of the crime. Moreover, in the simultaneous absence of precise just cause/just means permissibility criteria on the use of force, virtually all force exercised by governments could conceivably be construed as "terroristic."

Fifth, those definitions referring to "political" violence and/or objectives fail to demarcate clearly the identifiable boundaries of politics. What, exactly, are these boundaries? When, exactly, is violence unambiguously political? What, indeed, are the differences between political violence and the violence of ordinary criminality? As a jurisprudential matter, these questions have, in fact, been around for a long time, especially in connection with the international law of extradition and pertinent criteria of the "political offense exception."

Today, some states calculate that politically motivated violence, by definition, cannot be terrorism. Here, acts of violence that are committed on behalf of "national liberation," "self-determination" and/or "anticolonialism" fall outside the definition of terrorism. Hence, as observed by John F. Murphy: "Under this approach, sending letter bombs through the mails, hijacking airplanes, kidnapping or attacking diplomats and international business people, and indiscriminate slaughter of civilians could never constitute terrorism if the revolutionary groups committed them on behalf of a just cause." From the standpoint of international law, this approach ignores that the criterion of just cause is always augmented by the criterion of just means. As we have already noted, the latter standard has been brought to bear upon insurgent resorts to force by both the common Article 3 of the four Geneva Conventions of 1949 and by 1977 Protocols I and II. Indeed, even if these authoritative extensions of humanitarian international law had not been enacted, the Martens Clause would in and of itself obtain in relevant circumstances, confirming that "...civilians and combatants remain under the protection and authority of the principles of international law derived from established custom, from the principles of humanity and from dictates of public conscience."

It must also be understood that all law is rooted in natural law, and that natural law could never countenance violence against the innocent as permissible; that is, as outside the boundaries of terrorism. Recalling Cicero's classic expression of natural law in DE REPUBLICA, we see clearly why politically motivated violence by insurgents must be unlawful whenever it ignores the obligations of discrimination, proportionality and military necessity dictated by "right reason":

True law is right reason, harmonious with nature, diffused among all, constant, eternal; a law which calls to duty by its commands and restrains from evil by its prohibitions....It is a sacred obligation not to attempt to legislate in contradiction to this law; nor may it be derogated from nor abrogated.

For more than two thousand years, the idea of natural law has served as the ultimate standard of right and wrong, of lawfulness and unlawfulness. Already apparent in the ANTIGONE of Sophocles and the ETHICS and RHETORIC of Aristotle, this idea - tied closely to theology for many centuries - has placed law above lawmaking. At the same time, it is obvious that humankind has not only been generally indifferent to the law of nature, but has often even coupled this indifference with adherence to undiscovered "laws" that reject justice. Such coupling is evident, inter alia, in use of the "political" to excuse terrorism, to exclude, by definition (from the realm of terrorism) a number of rersorts to insurgent force that are simply not excludable under natural law.

We live at a moment in history where the realm of politics and the realm of crime are often more or less interpenetrating and overlapping, even - we daresay - interchangeable. (Who killed President Kennedy, "criminals" or "terrorists?"). Nevertheless, this interconnectedness was already understood by St. Augustine at the beginning of the fifth century. Describing human history, in the CITY OF GOD, as a contest of two societies, the intrinsically debased City of Man and the eternally peaceful City of God, the first society is characterized as little more than "a large gang of robbers." In an oft-quoted passage, Augustine recalls the answer offered by a pirate captured by Alexander the Great. When asked by the emperor what right he had to infest the high seas, the pirate replied: "The same right that you have to infest the world. But because I do it in a small boat I am called a robber, while because you do it with a large fleet you are called an emperor."

Of course, even if the concept of terrorism were suitably clarified and improved as per my recommendations, unless the states in world politics - especially major states such as the United States - begin to take seriously their counterterrorism responsibilities, the scholarship benefits of clarification/improvement will be moot. In this connection, U.S. validation of the P.L.O. regarding the Oslo agreement with Israel, and the subsequent Nobel Prize celebration of P.L.O. leader Yasser Arafat, fundamentally undermine the obligatory war against terrorism. It follows from all this that scholars must assuredly do their part to refine the terrorism concept, and that political leaders must now also do theirs in honoring the incontrovertible expectations of national and international law.

For the United States, these complementary expectations are both drawn from a common Higher Law tradition. Deducible, in turn, from a still-earlier tradition of natural law, the tradition of a Higher Law is one of the enduring and canonic principles in the history of the United States. Binding upon our political leaders in all circumstances, these leaders, following Blackstone in his celebrated COMMENTARIES, are expected "to aid and enforce the law of nations, as part of the common law: by inflicting an adequate punishment upon offenses against that universal law...." Understood in terms of the obligation of states to oppose terrorist crimes, this suggests a distinct American legal imperative. Of course, even apart from its Higher Law obligations, the United States is fully bound by the incorporation of international law expressed at Article VI of the Constitution and reaffirmed by various Supreme Court decisions.

During the Cold War, both American and Soviet leaders accepted narrowly geopolitical definitions of terrorism. For Washington, any insurgent force operating against an allegedly pro-Soviet regime was characterized as lawful ("freedom fighting" was the operative term), irrespective of the means used in that insurgency. Reciprocally, any insurgent force operating against a pro-American regime was characterized as terrorism, period. For Moscow, however, the United States was using the term terrorism simply to discredit what the Soviets alleged were legitimate movements for self-determination and associated human rights. In their view, insurgent force against what Washington freely called authoritarian regimes (e.g., El Salvador, Guatemala, Chile and, for a long time, South Africa) was not terrorism, as the United States had maintained, but "national liberation."

For the future, the United States, as the sole remaining superpower, must reject altogether such narrowly geopolitical definitions of terrorism. Aware that the Cold War is now over, and that the settled jurisprudential criteria that we have been discussing are consistent with its own incontrovertible norms and traditions, this country should begin immediately to articulate and to apply a single set of standards to insurgent resorts to force. Where such resorts express both just cause and just means, they should be recognized as permissible. But where they would lack just cause and/or just means, they should be recognized, and opposed, as terrorism.

This recommendation is offered for distinctly pragmatic operational reasons as well as for purely "academic" reasons of respect for justice and law. Once government officials and pertinent enforcement agencies are better able to distinguish between permissible and impermissible insurgencies under national and international law, because some scholars will at last have done their homework on the subject, they will be better able to allocate precious counterterrorism resources in a rational, cost-effective way. Rather than dedicate a substantial fraction of such scarce resources in a zero-sum environment to purposeless or counterproductive geopolitical diversions, these vital officials and agencies would be positioned to focus clearly and formidably upon the real threat to our safety. I hope that someone is listening!


LOUIS RENE BERES (Ph.D., Princeton, 1971) is the author of twelve books and several hundred articles dealing with international law and terrorism. He is a previous contributor to COUNTERTERRORISM AND SECURITY INTERNATIONAL.