It could be a bad riddle. Instead, it is one of the numerous guises in which contemporary terrorism presents itself. Although the instance may seem especially bizarre, it contains many of the elements common to terrorism as practiced during the last third of the twentieth century: A party nursing a grievance lashes out violently and unpredictably against targets bearing only the most tenuous connection to the object of its animus. No melioration is brought about by the strike, nor could any rationally have been anticipated by those who organized the operation. After bodies are bagged and reporters depart, political life proceeds much as before.

The subject of this essay is how to understand and evaluate the phenomenon of terrorism. An immediate obstacle that presents itself is that any purported definition of “terrorism” will itself be laden with moral and political baggage. Most individuals who employ violent means in their political activities prefer to speak of themselves as “urban guerrilla,” “revolutionary,” or some such. Their admirers and supporters generally comply. Thus the bromide “One person's terrorist is another's freedom fighter.” One need not accede to the implied relativism to acknowledge the absence of firm and generally accepted criteria of application for “terrorism” and its cognates.