I don't understand the recent tizzy over whether we can win in Afghanistan. Noticing that the central government isn't capable of governing Afghanistan is nothing new. That factor existed even back in the days when Afghanistan was the "good war" and the "real war on terrorism." We can win under those circumstances.
Complaining about not "resourcing" the fight and that we are doomed because we don't have enough troops is also bunk. We have enough troops--or can get them if we count everyone we can get. I thought so before the latest surge, too.
Just as in the Iraq War where many experts with calculators said we had too few troops to win almost until the day we won, you can't restrict yourself to just counting American troops, or even just Western troops. Every Afghan, be he a special forces type or a lowly local defense force militia type, counts in adding up the numbers. They aren't interchangeable with one another, mind you, but if given appropriate tasks they all contribute toward beating the jihadis.
With Pakistan making a proper effort on their side of the border, we can probably get by with 360,000 troops. With 150,000 foreign troops (by the end of the year--2/3 US), about 200,000 Afghan armed forces and national police, and 70,000 contract security forces (I'm going on memory, here), we're already well above what is needed by my rudimentary calculations made in the above linked posts. This doesn't count local warlords who are bought, local anti-Taliban militias, and local defense forces that we help set up and work with directly. We should have enough to win even if the Pakistanis falter in their efforts on their side of the border.
Nothing is certain in war, but I don't believe lack of resources is one of our challenges.