Terrorism is the use of violence to control the actions of others through enhancing their fear of the terrorists and what they stand for.

Two main varieties, "top-down" and "bottom-up" may be distinguished. These are perhaps best referred to as "terrorism by the strong" and "terrorism by the weak".

Terrorism by the strong ranges from that of parents to children, of policemen to the inhabitants of high-crime areas, to that of states to their weaker neighbors. The bombing of Hiroshima and Nagasaki was a form of terrorism by the strong. Although the allies were winning, they dropped the bombs on the weaker Japanese to terrorize them into surrender (among other objectives).

Terrorism by the weak is meant to enhance the fear of the strong of "what will happen" should they continue with their "oppression". It ranges from threats by witches (traditionally old and otherwise weak women) in primitive societies, to threats by unhappy students in recent high school catastrophes, to threats by minority peoples (or those who imagine themselves to be their representatives) against a ruling majority (as the Basques within a Spanish state), and by relatively weak governments against stronger (as the terrorist actions of Libya or Syria against Israel or the United States).

Unfortunately, leaders of strong societies use the term "terrorism" to refer almost exclusively to terrorism by the weak. Yet if we are to fully understand terrorism it is well to remember the more inclusive sense of the word.

Whenever terrorism is chosen to attain an objective, it should be remembered that it represents only one among several possible ways in which an actor or group might have chosen to achieve a desired objective. In many cases, it is only frustration and ignorance that makes terrorism seem the only answer.

Terrorism by the weak may be a personal or group phenomenon. The personal variant may have as its objective identity magnification, "getting people to notice me", even when the end result is likely to be the actor's death. Personal efforts with ostensibly more external objectives, such as "changing society" directly or through "getting people to notice my group or my favorite social issues", may be undertaken by individuals such as McVeigh, but are more commonly undertaken by groups. Nevertheless, there is often a personal component to the motivation of individuals involved in terrorism by the weak.(We will expand elsewhere on group terrorism by the weak, since this will be the primary focus of the web site.)

Unfortunately, terrorism often works. The terrorized do alter their behavior or thinking as the result of terrorist actions. If the terrorism succeeds at all, the terrorized take notice. Immediate and massive counter-violence is unlikely to erase this effect. Quite often, the longer-term result of terrorism is for the objectives of the terrorists to be at least partially attained.

To counter terrorism by the weak, three classes of responses may be distinguished: (1) Counter-terror, increasing the penalties for terrorist acts, that is, increasing the costs of terrorism for terrorist individuals or groups. (2) Improving defenses, thereby decreasing the ease of terrorist actions, for example through banning weapons from schools, controlling access to explosives, or improving physical shields for leaders appearing in public. (3) Reducing the conditions or feelings of inadequacy and helplessness of actual or potential terrorists. This last response may seem to reward terrorism, but in the long run in a civilized society it will provide the most effective answer to terrorism by the weak.