avenge fallen comrades or destroy their perceived enemies. Terrorism is a form of asymmetric warfare, and is more common when direct conventional warfare will not be effective because opposing forces vary greatly in power. Yuval Harari argues that the peacefulness of modern states makes them paradoxically more vulnerable to terrorism than pre-modern states. Harari argues that because modern states have committed themselves to reducing political violence to almost zero, terrorists can, by creating political violence, threaten the very foundations of the legitimacy of the modern state. This is in contrast to pre-modern states, where violence was a routine and recognised aspect of politics at all levels, making political violence unremarkable. Terrorism thus shocks the population of a modern state far more than a pre-modern one and consequently the state is forced to overreact in an excessive, costly and spectacular manner, which is often what the terrorists desire. The type of people terrorists will target is dependent upon the ideology of the terrorists. A terrorist's ideology will create a class of "legitimate targets" who are deemed as its enemies and who are permitted to be targeted. This ideology will also allow the terrorists to place the blame on the victim, who is viewed as being responsible for the violence in the first place. The context in which terrorist tactics are used is often a large-scale, unresolved political conflict. The type of conflict varies widely; historical examples include: Secession of a territory to form a new sovereign state or become part of a different state Dominance of territory or resources by various ethnic groups Imposition of a particular form of government Economic deprivation of a population Opposition to a domestic government or occupying army Religious fanaticism Responses Responses to terrorism are broad in scope. They can include re-alignments of the political spectrum and reassessments of fundamental values. Specific types of responses include: Targeted laws, criminal procedures, deportations, and enhanced police powers Target hardening, such as locking doors or adding traffic barriers Preemptive or reactive military action Increased intelligence and surveillance activities Preemptive humanitarian activities More permissive interrogation and detention policies The term "counterterrorism" has a narrower connotation, implying that it is directed at terrorist actors. Terrorism research Terrorism research, also called terrorism studies, or terrorism and counter-terrorism research, is an interdisciplinary academic field which seeks to understand the causes of terrorism, how to prevent it as well as its impact in the