Here's the punchline from the report released last week by the Commission on the Prevention of WMD Proliferation and Terrorism: "It is more likely than not that a weapon of mass destruction will be used in a terrorist attack somewhere in the world by the end of 2013."* That prediction was the lead in hundreds of news reports that the report generated last week.
The trouble is, in over 100 pages, the report's authors never justify their alarming claim. It's not that they do a poor job explaining how they arrived at the "more likely than not" in five years figure. They simply make no attempt to explain how they got there, other than to say that they talked to lots of experts.
They missed some. For a sober assessment of terrorists' utterly failed efforts to develop biological weapons, see Milton Leitenberg. On nuclear terrorism, see John Mueller or Michael Levi. Note that even Mueller's critics tend to agree that the odds of nuclear terrorism are generally overstated. See also Brian Jenkins and Michael Krepon.
Readers of the report should know that Commissioner Graham Allison has been making these sorts of predictions for some time, as John Mueller has noted:
[Allison] proclaims his "considered judgment" in his book: "on the current path, a nuclear terrorist attack on America in the decade ahead is more likely than not" (2004, 15). He repeats that judgment in an article published two years later without reducing the terminal interval to compensate — apparently the end date is an ever-receding target (2006, 39). Actually, he had been in the prediction business on this issue at least as early as 1995 when his imagination induced him boldly to pronounce, "In the absence of a determined program of action, we have every reason to anticipate acts of nuclear terrorism against American targets before this decade is out."
It would have been helpful if the authors offered some analysis of why past dire predictions have not come true before issuing new ones.
For more on this issue, come to Cato's upcoming counterterrorism conference. On January 12 and 13, a variety of experts will be here discussing the danger of terrorism and the danger of overreacting to it. I'm running a panel on terrorists' ability to use nuclear and biological weapons with Mueller, Leitenberg, Randy Larsen and a soon-to-be-named fourth expert.
*As I have written before, we should abolish the term, "weapons of mass destruction." It confuses the lethality of the weapons it subsumes and policy discussion. On the silliness of the phrase, read Owen Cote.