Definition of terrorism remains under debate

George P. Fletcher, Cardozo Professor of Jurisprudence, Columbia University School of Law, Project Syndicates

Every age has its enemies. In the mid-20th century, Fascists were the evildoers. After World War II, communists became civilization's nemesis. Now terrorists have become the designated masters of malevolence. The word "terrorism" appears in law books and legislation. Various civil sanctions apply to "terrorist organizations," and it can be a crime to assist one.

But it is not always easy to determine who "they" -- the terrorists -- are. Whether organizations are terrorist or not is largely a determination motivated by politics. The United Nations repeatedly passes resolutions against terrorism, but cannot agree on how to define the term.

Official definitions of terrorism are unpersuasive. The U.S. Congress defines terrorism as including a motive to coerce or intimidate a population or influence a government. But this formula does not clearly cover even the terrorist attacks of September 2001. If the motive of the airline hijackers was simply to kill infidels, their attack would fall outside the Congressional definition.

It is a mistake to try to define terrorism in the same way that we define theft or murder. There are too many contested issues. A better approach is to identify the issues that arise in thinking about terrorism and clarify why people experience terror from certain acts of violence. Then we can define terrorism with reference to all these variables, but without making any one of them decisive.

The three primary points of controversy are: The identity of the victims, the perpetrators, and the relevance of a just cause.

Must terrorism's victims be civilians? Some think so, but al- Qaeda blew up the USS Cole and most people regarded the killing of the sailors onboard a terrorist attack. The same logic applies in the guidelines for President George W. Bush's military tribunals, which treat those who attack military personnel and civilians alike.

There is a similar question about the perpetrators. Can terrorists be soldiers or state agents? Islamic states within the UN favor this position, and I think they are right. The International Criminal Court will prosecute heads of states for war crimes. By the same logic, state officials should bear responsibility for acts of terrorism committed under their authority.

The most controversial issue in defining terrorism is captured by the slogan: "One person's terrorist is another's freedom fighter." The problem is whether a good cause justifies using horrendous means. Islamic states think that it does, which puts them at odds with Western opinion.

Those who opt for terror always believe their cause is just. Sometimes it is, sometimes not. No American would be happy about branding the Boston Tea Party an act of terrorist aggression against British property. Nor would any Frenchman accept a description of the maquisards of the French Resistance as terrorists. Yet both committed acts of violence against property and people, and so do meet the conventional tests of terrorism.

There are other troubling borderline cases. What about the Stern gang's blowing up of Jerusalem's King David Hotel in order to liberate Palestine from the British? Is there good terror and bad terror? For some the political cause counts heavily, but in fact there are only a few historical cases in which most people actually disagree.

The nagging question remains: Why is terrorism different, why does it require a special definition, why are we more afraid of this form of violence than other criminal acts?

One reason is that terrorism is typically organized activity. In July 2002, when an Egyptian opened fire and killed two people waiting in line at the El Al counter at Los Angeles International Airport, the FBI decided that the suspect was not a terrorist because he was acting alone. Terrorists are organized, and the group can continue even after the individual is caught. That makes them more frightening than ordinary criminals.

Another reason for our greater fear of terrorism is that whereas ordinary criminals prefer secrecy, terrorists crave publicity. Effective terrorism always captures headlines. It is unexpected, with great shock value. Like good theater, terrorism always acts out some moral drama, and to strike terror in the public mind, terrorists must act in public, without guilt or remorse.

But suppose we try to define the attacks of Sept. 11, 2001, as terrorism by using the following formula: A violent, organized, and public attack by private parties on other civilians, without guilt, regardless of the justice of the cause. Problems still remain, because there are counter-examples for each of these six dimensions.

Sometimes the victims are military and the perpetrators are states, sometimes the cause appears to be just, and sometimes one person with enough weapons but no organization might wreak terror. A conspiracy to lace letters with anthrax might incite private terror. Some terrorists might feel remorse and guilt about their actions.

These counter-examples should not be surprising. Many definitions face this problem. The great 20th century philosopher Ludwig Wittgenstein proposed a different approach to troublesome definitions: Explaining concepts by the analogy of "family resemblances." Family members might share many physical features, such as height, skin tone, or hair color. Each member might share some of the common characteristics, but not all of them, with other members. There may be no single common feature, but all are readily identified as members of the same family.

The same can be said of terrorism. At least six features are relevant, but exceptions occur in each of the six. Complex definitions with built-in exceptions may make lawyers uncomfortable, but in the real world, they are perhaps the best we can devise.