DELHI — Without naming the United States as his source, Indian Prime Minister Manmohan Singh said recently: "We have been assured that Pakistan's nuclear weapons are in safe hands as of now. And I have no reason to disbelieve the assurance."

To his acute embarrassment, U.S. Secretary of State Hillary Clinton, soon thereafter, said the "unthinkable" could happen in Pakistan: Islamists could get "the keys to the nuclear arsenal." Which raises the question: Does America have a contingency plan to avert an Islamist takeover of Pakistan's "crown jewels" and, if so, can it work?

Pakistan's nuclear-stockpile security is handled by the Strategic Plans Division, which has under its command a special unit of about 1,000 troops. But as Clinton acknowledged, the Pakistani nukes are "widely dispersed," with storage sites extending beyond the Punjab heartland to Sind and Baluchistan provinces.