[Ayman al Zawahiri] “… is the likely successor to bin Laden, according to high-level national security officials both current and retired.
… the clear goal he has been actively pursuing is to carry out an attack on America using a Weapon of Mass Destruction (WMD) or, as a so-called “dirty bomb†is often referred to, a Weapon of Mass Effect (WME).
Based on interviews with a half dozen counterterrorism officials and experts with deep knowledge of Zawahiri, a portrait emerges of a leader who has for at least three years been quietly and effectively building the groundwork — theological and scientific — for Al Qaeda to complete an attack using WMD.
In 2008, Zawahiri wrote a book which presented his own theological grounding for the deployment of a nuclear weapon in America, and Al Qaeda’s sense of the religious justification for killing as many people as possible.
The book is a glimpse inside the religious fervor of a leader who is in many ways more ambitious than bin Laden was in trying to produce a “spectacular†terrorist event that will exceed the death and destruction caused on Sept. 11.”
http://www.globalpost.com/dispatch/news/opinion/columnists/110503/zawahiri-osama-bin-laden-al-qaeda