The use of a nuclear weapon would be the ultimate al Qaeda terrorist outrage. Over the past decade, however, the prevailing assessment of the likelihood of terrorist acquisition and use of nuclear (specifically), biological, chemical, or radiological (NBC/R) weapons has been reversed. In the 1990s, most policy makers and analysts were highly skeptical of warnings of terrorist use of these weapons. Today, the widespread assumption is that al Qaeda's acquisition of NBC/R weapons would be rapidly followed by their use -- that is, employment via the release of an agent, the dispersal of radiological materials, or the detonation of a nuclear explosive. This paper explores that proposition. In so doing, it seeks to illuminate the conditions and calculations that could shape al Qaeda's posture regarding employment of NBC/R weapons, as well as to highlight possible contributions to the overall U.S. war on terror "at the margin" of deterrence. Chapters are as follows: "Al Qaeda Use of WMD: Is there Even a Question?"; "Ground Truth: Much Smoke, Some Fire?"; "Who Is al Qaeda"?; "Operational Code: Implications for NBC/R Employment?"; "Bin Laden, a Restored Islamic Caliphate, and a Nuclear Blackmail-Deterrence Strategy"; and "Implications for U.S. Posture and Policy." Specific topics include reports and allegations of al Quaeda's efforts to purchase NBC/R weapons, hard evidence, and aborted plots or operations; Al Qaeda's organizational fluidity and personnel diversity, pattern of operational preparations, and attack profile; Osama Bin Laden's statement that it is the Muslims' "religious duty" to try to possess NBC/R weapons; nuclear use and the new Caliphate; al Qaeda and "state-like" behavior; the United States' deterrence leverage points; and heightening Bin Laden's "self-deterrence."

"July 2005."