"A more serious objection to the American and British modernization plans is that they offer no realistic security against terrorism. Suppose al Qaeda detonates a nuclear bomb in Times Square. Suppose that the weapon was stolen from an old Soviet depot, meaning no "return address" for purposes of retaliation. Suppose, also, that al Qaeda threatens to detonate five other bombs if the U.S. does not meet a list of its demands. What use would deterrence be then? Against whom would we retaliate, and where?

...

"Even nihilists have something they hold dear that can be threatened with deterrence," says Max Singer, a collaborator of the great Cold War theorist Herman Kahn. "You need to know what it is, communicate it and be serious about it."

Would it hinder Islamist terrorists if the U.S.'s declared policy in the event of a nuclear 9/11 was the immediate destruction of Mecca, Medina and the Iranian religious center of Qom? Would our deterrent be more or less effective if we deployed a range of weapons, such as the maligned "bunker buster," the use of which a potential adversary might think us capable? How would the deployment of a comprehensive anti-ballistic missile shield alter the composition of a credible deterrent? Does it make sense to adhere to the NPT regime when that regime is clearly broken?"

http://online.wsj.com/article/SB117435627565742300.html