The withdrawal of Western forces and absence of a common enemy could exacerbate fractures between rival insurgent organizations. Moreover, a reduced Western presence in Afghanistan will prompt the war to morph in focus from a West vs. Muslim conflict to a Muslim vs. Muslim conflict. This transformation could have serious consequences for Taliban fundraising activities in the broader Muslim world.And a cogent summary:
While the picture painted by most of the western media in Afghanistan is pessimistic, the way forward in Afghanistan, even under a strategy of a limited-win, will neither be easy nor assured of success. There remains a significant possibility that the West is simply too war weary to maintain even modest commitments of troops and funds past 2014. Moreover, even if the strategy of a limited-win is fully realized, the West is still left propping up a corrupt and ineffectual government for an indefinite period of time. Nonetheless, abandoning Afghanistan entirely will have serious adverse consequences for the stability of the region and the security of the West, which is why a strategy of a limited-win may prove the better of several bad alternatives.
The medium-term future is surely likely to remain one of limited financial and military resources, as the the number and nature of trouble spots around the world proliferates. Afghanistan cannot remain on life support indefinitely; after a decade of commitment from the West, the country must learn to stand on its own two feet.