The possible use of weapons of mass destruction (WMD) by terrorists has been a subject of concern for decades and has seemed more pressing since March 1995, when a Japanese cult known as Aum Shinrikyo spread the nerve gas sarin in the Tokyo subway system. Yet, until October 2001, terrorist groups around the globe refrained from using WMD. Experts agree that the production of chemical and biological weapons, however crude, is clearly within the reach of many terrorist groups. Why, then, have they refrained from using them? The only plausible explanation is that the use of these weapons has been considered taboo. For many terrorist groups, presumably, the proscription has not been based on moral convictions but on the pragmatic assessment that crossing the line of using universally prohibited weapons would result in a devastating response.

This taboo was broken on September 11, 2001, a day that marked a turning point in the history of terrorism. The number of fatalities from these attacks was about 20 times that of the worst previous act of terrorism. Beyond the tally of casualties, the attacks constituted a direct challenge to the world’s mightiest nation. Terrorism made a quantum leap from being simply a nuisance to being a major threat to world order. The implications of the September 11 attacks are even more enormous. The breaking of the taboo may bring about an era in which terrorism of monstrous proportions will dominate the world scene. A first indication of the new threat has come from the anthrax-laced letters that circulated following the September 11 attacks. On the other hand, the shock of these attacks may result in policies that will effectively deter international terrorism in the future. At this critical juncture, it is important to examine the history of attempts to deter international terrorism so as to draw lessons for the future. The discussion that follows is founded on relevant Israeli and US experience.

Legal Problem or War?

Terrorist activity by groups or individuals based within the country against which they operate is a criminal matter that can and should be handled by the legal system of that country. However, the problem of deterring terrorism is much more complicated in situations of international terrorism, with terrorists based outside the jurisdiction of their adversary state. Under these circumstances, the ordinary deterrent effect of the law is not at the state’s disposal.

Policies for coping with international terrorism may rest on either one of two basic conceptions: viewing terrorism as a legal problem or treating it as a form of war. With a few exceptions, the United States has so far adopted the first approach, whereas Israel has pursued the second. The different approaches can be illustrated by two historical episodes. Following attacks on Israeli civilian airliners by a terrorist group based in Lebanon, in December 1968 Israeli paratroopers raided a Beirut airport and destroyed 13 Lebanese civilian airplanes. On the other hand, after the hideous mid-air explosion of Pan Am Flight 103 by Libyan agents in 1988, the United States chose to indict two mid-level Libyan officials. Of course, Libya refused to extradite them, and only after years of economic sanctions were they sent to stand trial in a neutral country. In the end, for a state-sanctioned attack that all but amounted to an act of war against another state, one of the two suspects was sentenced to prison for life, and the other was released due to lack of evidence.

Although US law since 1986 has allowed the extraterritorial arrest of terrorists, in actuality, the United States has only managed to bring to justice one minor-league terrorist on the basis of this law: a Lebanese named Fawaz Younis, after a very costly operation that lured him into international waters in 1987. This law cannot be expected to solve the terrorism problem because it is only applicable on extremely rare occasions. Whereas the legalistic approach is certainly justified with respect to domestic terrorism, it is inherently handicapped in dealing with adversaries abroad, especially in situations where terrorists enjoy a safe haven in a country that sponsors their violent activity. The problem has been exacerbated by the United States’ anti-terrorist rhetoric. Due both to the United States’ status as a prime target for terrorists around the globe and to domestic and international political considerations, US politicians have beaten loud the drums of combating terrorism, thus creating public expectations that they cannot fulfill.

Deterrence and Use of Force

It is practically impossible to arrest terrorists in countries where they enjoy the protection of the government, and it is almost as difficult to apprehend them in unruly territories such as Lebanon. As opposed to these measures, it is much more feasible to punish them without bringing them to trial. Such extra-judicial punishment takes the form of cloak-and-dagger operations when it is aimed at individual terrorists or reprisal military strikes when it is directed against a terrorist organization’s strongholds, headquarters, or training camps. Nevertheless, there is a difference between feasibility and effectiveness, as the Israeli experience shows.

Cloak-and-dagger operations. After Palestinian International attacks against Israeli targets reached a peak with the 1972 murders of members of the Israeli Olympic team at the Munich Summer Games by the Fateh Black September Organization, Israel adopted a new policy in its struggle against terrorism: a campaign of assassinations against terrorist operatives, especially in Western Europe, the main arena of their operations. According to accumulating reports, from 1973 through 1999 approximately 30 terrorist operatives were assassinated by Israeli agents. Ostensibly, the assassinations had two objectives: to disrupt terrorist operations in process by eliminating the persons involved in their preparation, and to deter other active or potential terrorists.

In all likelihood, the elimination of key terrorists thwarted some planned terrorist attacks. It is also conceivable that the need to be on alert and to take extensive precautions, such as frequent changes of residence, further interfered with the terrorists’ ability to carry out operations. However, Palestinian terrorist attacks in Western Europe continued despite the Israeli campaign. We must conclude, therefore, that the assassinations deterred neither the individual terrorists nor the organizations that sent them.