【正文】 ast resort if prevention has failed. Prevention takes place ‘‘before the fact.’’ Legal rules backed up by the threat of sanctions presumably serve the purpose of prevention by making norm violation a costly risk. A general threat of sanctions attached to given categories of acts is, however, unable to prevent specific incidents, for instance of murder, robbery, embezzlement, or terrorism. Terrorists do behave rationally, but for many of them being caught, detained, or even killed are discounted costs。 here the ‘‘Law’’ and available law enforcement measures have no preventive effect. Prevention strategies can be either defensive, trying to protect the potential victim from attack, or offensive, trying to incapacitate the potential perpetrator—either directly by physically destroying him, or indirectly by making him unable to act and starving hi m out. There is a fluid boundary between these seemingly clearcut categories. Border controls, for example, are both a defensive and an offensive measure: they protect the potential victim, but they also constrain the action space of terrorists. Promising control strategies of both types depend on the kind of threat. If the threat is a specific one, ., if it is possible to anticipate who might do what, where, and when, a feasible offensive strategy could be to detain the person or persons about to mit the act, and protection (sealingoff) of the threatened site would be a sensible defensive strategy. This strategy has been successful in the case of the socalled Millennium scare. Here at least the critical time was known (around New Year’s Eve), and certain sites such as puter centers and places of celebration appeared to be especially threatened. All agencies in the security munity were on alert, and all threatened sites were highly protected. In the end, nothing happened. One terrorist who planned to bomb the Los Angeles airport was caught when he tried to enter at the Canadian border. The attack was not a specific threat。 when it happened, it came as a plete surprise to most—not so much with respect to the organization behind it, but with respect to the time, the place, and above all the kind of attack, ., by using hijacked civilian aircraft as missiles. If there is no credible lead as to the place, the time, the kind of a threat, and the identity of the potential terrorists, only highly general defensive measures such as 濟(jì)南大學(xué)畢業(yè) 論文外文資料翻譯 3 rigid control over the movement of people, vehicles, and goods might serve. The extent to which such preventive measures are acceptable differs。 in authoritarian regimes, potential troublemakers may be detained (or even murdered), but in a constitutional state with a legalistic culture, the actions of public authorities are constrained by law. The first condition of successful control is therefore to recognize the existence of, and identity of, a potential enemy. Such recognition may not permit us to anticipate specific terrorist acts, but it does permit us to develop a more pointed offensive strategy, ., to incapacitate the person, group, or organization presumably planning unspecified terrorist acts. This could either be done directly by physical destruction, or indirectly by cutting off their supplies and narrowing their action space. WHY PREVENTION FAILED: THE CHARGE The Report