NATO see Afghanistan as their sphere of influence. Also I dont believe for a single second that NATO is unaware of who is present in Afghanistan, what they are doing to Pakistan and what India's involvement is. Their intention has always been to destabilise Pakistan to make us easier to control and manipulate. If you view an incursion into Afghanistan on that basis, it's not hard to imagine that NATO is well capable to engineering a situation where they can claim that Pakistan has encroached on their interests. A false flag if you like. Then we are in a world of problems. NATO doesnt even need to do the fighting themselves, there are hundreds of thousands of Afghans who will fight Pakistan for a bowl of rice a day. That's just the way they are. My humble opinion of course, but I think we should keep it artillery, drones and hired militias. Get the Afghans to do the dirty work in their own country. Why should we risk lives?