Comparative psychological studies indicate that there is not one terrorist mindset. A theme common among disparate groups is the strong need of marginally alienated individuals to join a group of like-minded persons with a similar world view that 'it's us against them.' This need to belong gives particular force to the power of group dynamics. While ideology using language that frames everything in black or white holds terrorist groups together and provides a rationale for action, terrorists do not commit acts of violence for ideological reasons. Reactive retaliation may not deter terrorists, but reinforce their mindset and further unite the group against an outside enemy. The crucial factor in estimating the effects of counterpolicies is identifying the locus of control within the terrorist group. Terrorists cannot be forced to give up terrorism, for to do so would be to lose their reason for being. In the short run, retaliatory policies can have a deterring effect on state-supported and directed terrorist groups since they are really a paramilitary group under central government control. In the long run, the most effective policy is one which makes the terrorist career less attractive, facilitates terrorists leaving the group, and reduces external support. 1 figure and 19 references. (Author abstract modified)