Since the terrorist attack on the World Trade Center in 2001, the western world has undergone an order-of-magnitude increase in its concentration on national security. Among the chief concerns of security professionals is the threat of weapons of mass destruction (WMD). Such weapons are classified according to their nature, as chemical, biological, radiological, or nuclear (CBRN).
The danger posed by the acquisition of such weapons by Islamic terrorist organizations such as Al-Qaeda, the Islamic State (ISIL), and scores of similar violent non-state actors (VNSA) is obvious. And these groups have repeatedly expressed their willingness to make use, in particular, of widespread, mass-casualty WMD attacks in the cause of jihad. The clearest example in recent years has been the release of WMD in the form of toxic industrial chemicals by the forces of ISIL in Syria.
But it seems that it is the lone actors and autonomous cells within these groups that constitute the most serious threat, since their varied nature and often obscure motives make them the most difficult to detect. Since 2012, the most common type of attack from such lone terrorists has employed chemical agents.
But despite the palpable reality of the threat from Islamic terrorism and its growth in recent decades, its magnitude has been overstated. Given current restraints on their resources and the limited nature of their capabilities, a genuine WMD attack will be difficult for even the most determined of terrorist groups to mount. Except in the extremely unlikely scenario of the theft of a nuclear or biological weapon from a state arsenal, current non-proliferation measures should serve to curtail the dimensions of terrorist attacks. Still, as one security professional soberly observes, "...with the stakes as high as (they are) with WMD, the defense cannot afford to falter even once."