Terrorism is a particular species of political violence. It is violence or the threat of violence against noncombatants or property in order to gain a political, ideological, or religious goal through fear and intimidation. Usually symbolic in nature, the act is designed to have an impact on an audience that differs from the immediate target of the violence. While the attacks on the United States of September 11, 2001, and their aftermath have tended to focus international attention on radical Islamist terrorism, the spectrum of terrorism is broad and diverse, as illustrated in Figure 1. At the top tier are the three major divisions of political, criminal, and pathological terrorism.

Figure 1 New Typology of Terrorism

Source: Adapted from Schmid (1984).

There is a widespread assumption in the ...