Bruce Hoffman, the director of the Centre for the Study of Terrorism and Political Violence, has written a clear summary of some of the major historical trends in international terrorism. He makes careful distinctions between the motivations that drive political (or ethno-nationalist) terrorism and religious terrorism, and he also shows why the rise of religious terrorism, coupled with the increased availability of weapons of mass destruction, may foretell an era of even greater violence. In the past, Hoffman argues, the main goal of the terrorist was not to kill, but to attract media attention to his cause in the hope of initiating reform. "For the religious terrorist," however, "violence is first and foremost a sacramental act or divine duty executed in direct response to some theological demand or imperative ... religious terrorists see themselves not as components of a system worth preserving but as 'outsiders,' seeking fundamental changes in the existing order." Hoffman does not "choose sides" in this framework, pointing to the bombings of the World Trade Center and Oklahoma City and to the sarin nerve gas attacks in Tokyo in order to demonstrate that fundamentalists of any religious denomination are capable of extreme acts of terrorism.