HarvardIt is five years since the attacks on the World Trade Center and the Pentagon, but Western democracies have not even begun to address seriously, and in a nuanced way, the moral and intellectual challenges posed by the relatively new phenomenon of mass-casualty suicide terrorism. The traditional paradigm by which we have long confronted harmful conduct — waiting until the harm occurs and then punishing the harm-doer to deter others — cannot work with the suicide terrorist who welcomes the ultimate punishment. A new paradigm, relying more on anticipatory and preventive measures, must be considered. But such measures carry with them considerable dangers to civil liberties. The debate thus far has been largely an unilluminating clash of ideological extremes with one side arguing against any compromise with the old deterrent-civil liberties model, and the other side insisting that the need to prevent mass-casualty terrorism trumps traditional concerns over civil liberties.