So let's talk logistics.
President Obama has ordered roughly two more divisions into Afghanistan. I'm having a rough time trying to figure out what the rate of supply is for an Army division in combat.
A US Army division in Europe during WW2 consumed about 600+ tons of goods a day, which was ten times or so of the rate of consumption from WW1. I've seen reports that 1,000 tons a day is a rough working figure.
A standard 40' shipping container can hold 30 tons (short tons, about 26.7 metric tons) of cargo. A thousand tons of stuff would take 34 containers a day. That may include fuel, so we can cut the number of containers and add in tanker trucks, probably a lot more tanker trucks to support the mechanized vehicles and helicopters. Two divisions, at least 70 more trucks of stuff have to arrive in Afghanistan each day and my wholly unsupported guess would be maybe 100 truckloads. That's just to support the additional guys, you can quadruple that for the amount of cargo needed to support all of the foreign forces and we are also supplying the Afghan Army, so maybe quintuple that.
That is a shitload of stuff.
Go look at a map of South and Central Asia. See if you can find how the stuff gets to Afghanistan. There are few options to move that amount of stuff other than by ship to Karachi and then by truck into Afghanistan, a supply line that runs more or less right through territory disputed by Islamic militants. Afghanistan has no railroad network of note, but, as experience from back in the days of T.E. Lawrence has shown, railroads are very vulnerable to demolition devices. The trucking supply line has been attacked by militants before and most assuredly will be again.
Stuff cannot be shipped in through Iran. It may be possible to send supplies through Russia and the neighboring `stans, but the price extracted by those nations may be too high and the transshipment of war supplies through Russia may be politically untouchable, even for the Russian government.
Even if all that stuff can be sent without sporadic interdiction by the militants, there is still the issue that we are propping up arguably the most corrupt national government in the world, a government that will assuredly fall as quickly as did the government of President Najibullah after the Red Army left.
Pakistan, regardless of how much our government prods them, is still playing a lesser version of the Great Game with India. The object of their version of the Great Game, as it was between the British and Russian Empires, is control of Afghanistan. Pakistan fought three formal wars with India (all of which they lost) and has been sponsoring a sputtering guerrilla war over Kashmir for decades.
Elements of Pakistan's intelligence service have always seen the Taliban as a counterweight to India. They may be closer to recognizing that the militants recognize no borders whatsoever and that the militants now see Pakistan itself as a prize to be won.
Pakistan's offensive in South Waziristan has apparently done little other than force the militants to relocate. As any study of any insurgency-type war will show, measuring how much territory a uniformed army claims to control is a false metric. In any event, the Pakistanis are concerned about their own militants, not the Afghan Taliban.
You have little chance of winning a counter-insurgency war if your enemy has a place where they can regroup, rearm, retrain and where you cannot go. That is the situation now. If Pakistan will not commit to helping to defeat the Afghan Taliban, then it matters little if the President sends in 30,000 more troops or 100,000.