International terrorism became a prominent issue in the late 1960s, when hijacking became a favored tactic.

The era also gave us our contemporary sense of terrorism as highly theatrical, symbolic acts of violence by organized groups with specific political grievances.

Religiously motivated terrorism is considered the most alarming terrorist threat today. Groups that justify their violence on Islamic grounds- Al Qaeda, Hamas, Hezbollah—come to mind first. But Christianity, Judaism, Hinduism and other religions have given rise to their own forms of militant extremism.

Terrorism is continually changing. While at the surface it remains "the calculated use of unlawful violence or threat of unlawful violence to inculcate fear…" it is rapidly becoming the predominant strategic tool of our adversaries. As terrorism evolves into the principal irregular warfare strategy of the 21st century, it is adapting to changes in the world socio-political environment.

As a conflict method that has survived and evolved through several millennia to flourish in the modern information age, terrorism continues to adapt to meet the challenges of emerging forms of conflict, and exploit developments in technology and society. Terrorism has demonstrated increasing abilities to adapt to counter-terrorism measures and political failure. Terrorists are developing new capabilities of attack and improving the efficiency of existing methods. Additionally, terrorist groups have shown significant progress in escaping from a subordinate role in nation-state conflicts, and becoming prominent as international influences in their own right.

Terrorists are improving their sophistication and abilities in virtually all aspects of their operations and support. The aggressive use of modern technology for information management, communication and intelligence has increased the efficiency of these activities. Weapons technology has become more increasingly available, and the purchasing power of terrorist organizations is on the rise. The ready availability of both technology and trained personnel to operate it for any client with sufficient cash allows the well-funded terrorist to equal or exceed the sophistication of governmental counter-measures.

All terrorist acts are motivated by two things:

• Social and political injustice: People choose terrorism when they are trying to right what they perceive to be a social or political or historical wrong—when they have been stripped of their land or rights, or denied these.

• The belief that violence or its threat will be effective, and usher in change. Another way of saying this is: the belief that violent means justify the ends. Many terrorists in history said sincerely that they chose violence after long deliberation, because they felt they had no choice.

The type of target selected will often reflect motivations and ideologies. For groups professing secular political or social motivations, their targets are highly symbolic of authority; government offices, banks, national airlines, and multinational corporations with direct relation to the established order. Likewise, they conduct attacks on representative individuals whom they associate with economic exploitation, social injustice, or political repression. While religious groups also use much of this symbolism, there is a trend to connect it to greater physical devastation. There also is a tendency to add religiously affiliated individuals, such as missionaries, and religious activities, such as worship services, to the targeting equation.

The Intent of Terrorist Groups

A terrorist group commits acts of violence to: