I don't know either, but that certainly sounds like a Sy Hersh work, and he has, from what I've seen, been out in front of a lot of people.

Be nice to America. Or we'll bring democracy to your country.

I can dimly remember a Newsweek article roughly three years ago. There was speculation about rapid reaction special forces stationed on Diego Garcia trained exclusively for taking control of Pakistani nuclear facilities.

"If you know your enemies and know yourself, you will not be imperiled in a hundred battles." Sun Tzu

Kudos to your memory. Seymour Hirsch wrote on this in 2001.

Annals of National Security: Watching the Warheads: The New Yorker

Nonetheless, in recent weeks an élite Pentagon undercover unit--trained to slip into foreign countries and find suspected nuclear weapons, and disarm them if necessary--has explored plans for an operation inside Pakistan. In 1998, Pakistan successfully tested a nuclear device, heralded as the Islamic world's first atomic bomb. According to United States government estimates, Pakistan now has at least twenty-four warheads, which can be delivered by intermediate-range missiles and a fleet of F-16 aircraft.

[...]

In recent weeks, the Administration has been reviewing and "refreshing" its contingency plans. Such operations depend on intelligence, however, and there is disagreement within the Administration about the quality of the C.I.A.'s data. The American intelligence community cannot be sure, for example, that it knows the precise whereabouts of every Pakistani warhead--or whether all the warheads that it has found are real. "They've got some dummy locations," an official told me. "You only get one chance, and then you've tried and failed. The cat is out of the bag."

The fact is that what we're experiencing right now is a top-down disaster. -Paul Krugman