In an article published in the Washington Times on Mar. 30, the former U.S. assistant secretary of defense and author of “Nuclear Terrorism The Ultimate Preventable Catastrophe” Graham Allison wrote: Before Sept. 11, 2001, most Americans found the idea that international terrorists could mount an attack on their homeland and kill thousands of innocent citizens not just unlikely, but inconceivable. The view that terrorists are preparing even more deadly assaults seems as far-fetched to them as the possibility of terrorists crashing passenger jets into the World Trade Center did before that fateful Tuesday morning.

To assess the threat of nuclear terrorism, it is necessary to answer five questions:
1. Who could be planning a nuclear terrorist attack? 2. What nuclear weapons could terrorists use? 3. Where could terrorists acquire a nuclear bomb? 4. When could terrorists launch the first nuclear attack? 5. How could terrorists deliver a nuclear weapon to its target?
The crucial challenge to this principle today is Iran.