"American Hiroshima" At 50% Chance Of Detonation Within 10 Years

How likely is it that terrorists will some day be successful at detonating a nuclear device in a major American city? That was the question debated in an online forum sponsored by the Council on Foreign Relations this week. And while Harvard's Graham T. Allison and the CFR's Michael A. Levi may disagree over the likelihood of such an attack, they agreed it is a serious threat and much more needs to be done to avoid the disastrous consequences. "In the hotly contested American presidential election in 2004, the two candidates agreed on only one fundamental point," he said. "In the first televised debate, they were asked, what is 'the single most serious threat to the national security to the United States?' President Bush, answering second, said: 'I agree with my opponent that the biggest threat facing this country is weapons of mass destruction in the hands of a terrorist network.'" Allison cited other authorities, including former Sen. Sam Nunn, who is on record as saying the likelihood of a single nuclear bomb exploding in a single city is greater today than at the height of the Cold War. Perhaps no one, however, has studied the issue more thoroughly than Allison. In his book, based on the current trend line, he concludes the chances of a nuclear terrorist attack in the next decade are greater than 50 percent. He said former Secretary of Defense William Perry believes that assessment underestimates the risk. "From the technical side, Richard Garwin, a designer of the hydrogen bomb who Enrico Fermi once called, 'the only true genius I had ever met,' told Congress in March he estimated a '20 percent per year probability with American cities and European cities included' of 'a nuclear explosion -- not just a contamination, dirty bomb -- a nuclear explosion.'