General Petraeus is painting a relatively rosy picture of the path forward in Afghanistan. US intelligence agencies are saying somewhat else. It can be summed up thus (By Strafor):
"As U.S. Col. Harry Summers so clearly articulated, negotiation is achieved militarily when military power is applied in such a way as to impose upon the enemy a choice: negotiate on American terms and on American timetables, or be destroyed. Negotiation with the Taliban must be understood first and foremost as lacking that latter possibility."
If the Taliban do not actually see their position weakening over time, effective negotiations will not occur--they may be willing to humor negotiations at the last minute as NATO leaves, in order to avoid a civil war, but the NATO bargaining position at that point will be nearly zero.
The question that's not yet clear to me is this: how strategically effective is the US "Surge" in Afghanistan? How effective are the attacks on senior leadership and the counter-insurgency movements on the ground? I just don't know.