Re: Defining ‘strategic depth’
A gross oversimplification.
For example, the author of this article seems unaware how close PAF airbases are to the Indian border. An Afghanistan that is firmly under Pakistan's heel would enable airbases to be positioned sufficiently far from India to enable aircraft to operate with lower risk from Indian attack. It also enables supply infrastructure to be located further away from the front lines.
The author also easily falls into the fallacy of thinking nuclear weapons are the solution in conflict. Pakistan's nuclear arsenal is an insurance against first use by India; in addition, just like the Pakistani army, Indian forces are capable of operating in a post-nuclear battlefield.
Indeed, India is better suited for this simply through having more manpower in its army. It would have more soldiers who survive the nuclear exchange. A nuclear war is likely to still leave military forces in play that would be able to fight to secure what is left. (which will most likely still be a lot that is of value).