In this chapter, several questions are raised regarding the attacks on the United States on September 11, 2001, specifically on the attacks, the perpetrators, and how the United States responded. The chapter begins with a look at what is terrorism. This is followed by the problem in explaining perpetrators as suffering from some kind of serious psychopathology. The immediate problem identified with this explanation is that the attacks were well-planned and well-executed, integrating groups of terrorists. Another explanation for the September 11 attacks of terrorism is the emotion of hatred. However, there is no evidence that the perpetrators were suffering from insult or frustration. It is not the personal experience of the individual terrorist that makes him/her angry but the experience of the group with which the terrorist identifies. Hostility, anger, and hatred are not prime movers of political violence. Rather, they are the reflections of in-group attachment in relation to varying perception of out-group threat. The September 11 terrorists attacked the United States for supporting governments that repress Muslim fundamentalists contesting for political power in their own countries. Terrorist aggression is instrumental: they aim to inflict long-term costs on their enemy and to gain long-term advantage for themselves. Terrorism is properly understood as the continuation of politics by other means. However, the response to terrorism can be more dangerous than the terrorists. References