From: The Future of Terrorism by Luke Alison (SmallWarsJournal)

Many groups still view the application of terror as a useful approach. While political dissatisfaction seems largely endemic to the human condition: the thought that new sensational displays of violence might help reorder society is never entirely outmoded. The continued appeal is the notion (at least conceptually) that terrorism can become easier to apply, but harder to counter. Basically, the framework here is a type of schism that increasingly negates strategic prevention, but intentionally courts sanguinary pitched battles. In that respect, someone is always thinking about what comes next, and:

“There are several reasons behind this trend. One is the terrorists' natural tendency to ‘out-do’ their previous attacks, stimulated by the perception that if the present level of violence has thus far failed to succeed in forcing a radical change in the status quo, the campaign needs to be intensified. Another reason is the fact that no matter how horrific a terrorist campaign might be, the intended audiences become desensitized to the current level of violence over time, forcing the terrorists to escalate further in order to maintain or heighten the atmosphere of panic and fear among the general population, and to stay in the spotlight. An escalation in terrorist violence is also sometimes stimulated by the actions of other organizations with which the given group competes for power or popularity. Another reason for the gradual escalation of overall terrorist violence over time has been the formation of new groups. Upon emergence, new violent organizations usually do not undergo the full step-by-step process of radicalization, but rather pick up at the level of violence where other organizations active in the same struggle have left off. Alternatively, many existing organizations can give birth to new formations through the process of splintering, which usually results in the new entity being more radical and more violent than the core group.” (Adam Dolnik & Keith M. Fitzgerald, Negotiating Hostage Crises with the New Terrorists, )