Terrorism is violence for effect rather than for the physical impact on its actual target. Developments in world communications have enabled terrorists to gain wide publicity for their causes. Until recently, however, the actual destruction resulting from terrorism has been small. This is likely to change in the next 10-20 years because of new vulnerabilities and new weapons. Civil aviation, energy systems, and nuclear power facilities are particularly vulnerable to terrorism, and the feasibility of a terrorist-posed nuclear threat is currently an issue of heated debate. Recent weapons research has focused on individual weapons and the miniaturization of major weapons and guidance systems, such as the American Redeye or the Soviet Strela shoulder-five anti-aircraft missiles. Other new weapons being developed include man-portable anti-tank weapons, disposable lightweight silent mortars, and weapons for urban warfare. Although these are military weapons, there is no evidence that terrorists are not interested in better weapons than they now use. The possession of advanced weapons can reinforce the dramatic effect of terrorist activities. The notion that widely available, easy-to-operate, highly accurate, and highly destructive portable weapons are going to stabilize the defense of any country deserves critical examination in view of their possible use toward nonmilitary targets. Furthermore, although countervailing technology exists, full application of such technology implies unwelcome control over human liberty.