Unlike Iraq, the Afghan surge has not worked. It has been more than a year now, and I don't think it will ever work. Afghanistan is fundamentally different than Iraq because there are no oil revenues to divvy up among the factions. Given the scarce resources, warlordism prevails and will continue to prevail long after we leave.
Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.