"The real difficulty, of course, is that a Pakistan openly attacked in retaliation might in turn retaliate with nuclear weapons to protect the raiders. That is just how destabilizing an Islamic bomb is, a thing that the people so blandly accepting of Iranian nuclear weapons had better think about." Well stated. I to have wondered when an Al Qaida/Taliban nuke (provided by Pakistan of course) will be used in Afghanistan against American forces. I can think it's entirely possible. I'm sure the Pakis will deny providing it to them. We'll have to nuke them back of course. Horrible state of affairs over there.
I don't think it would be provided by Pakistan directly, but the A.Q. Kahn turd is still loose in Pakistan—and he probably still has the wherewithal to do such a thing.
Pakistan knows we would REALLY annihilate them if they did such a thing, but Kahn, on the other hand, is only an individual.