ABSTRACT
In general, the ideal way to counter any particular terrorist threat is to identify it long in advance and to act to prevent it from materializing, thus obviating the need for mitigating its effects or cleaning up the mess after an attack has occurred. Clearly, this is not always possible, which is why we must attempt to structure the environment so that the threat becomes infeasible (see Chapter 11), as well as harden potential targets and prepare to respond to attacks (see Chapter 12). Yet, one of the primary-and arguably the most effective-means of countering the jihadist use of weapons of mass destruction (WMD) is through early warning and prevention (in the sense of tactical or operational interdiction or disruption), which falls mainly within the purview of the intelligence and law enforcement domains. Although their missions are in some ways symbiotic, there has historically more often than not been a functional gap between law enforcement1 and intelligence institutions,2 where each set of actors has developed a distinctive, and not always compatible, culture and set of standard operating procedures.
