Marrying Prevention and Resiliency

The uncertain nature of the terrorist threat is a fundamental challenge in the design of counterterrorism policy. To deal with this uncertainty, the author recommends a capabilities-based, portfolio approach to terrorism prevention planning, drawing examples from aviation security policy. While traditional terrorism-prevention measures seek to prevent all damage by stopping them completely, mitigation and resiliency measures buy a lower, but more certain, payoff: preventing only some of the damage from attacks, but doing so predictably across the many different ways in which threats might become manifest. In a prevention and mitigation portfolio, some measures would reach for the highest payoff of completely preventing attacks, while others would provide a more-stable protective return by limiting the damages any terrorist operation or other incident. Protective portfolios should be assessed to determine which will perform well across a range of possible futures and be judged less sensitive to threat uncertainty — and therefore more attractive given an uncertain future.