I think what Fuchs meant (correctly) was that having Nukes makes Pakistan "too big to fail" and guarantees that bailouts will be forthcoming while also guaranteeing that any strategy of bombing or intervening directly will appear too risky. It also provides a very very valuable potential export item, to be used (i.e. sold to Saudi Arabia) if all else fails.
The only reason I am not jumping on board the "ISI is brilliant" bandwagon is because there was another choice and for the people of Pakistan (as opposed to its military-bureaucratic elite) that choice would have been much better ..to dump its "India-centric", nuke-protected-jihadi-based interventionist foreign policy and think about improving living standards and governance via the old-fashioned route (trade, industry, culture, etc). But as long as you buy the nationalist BS surrounding these matters, Pakistan's "core professionals" have played the US brilliantly and will continue to do so.
Groundhog day indeed.