I've been contributing to some other venues on this topic, so I thought I would add some paraphrased thoughts from that, here as well.
The WE [ISAF] are HERE [Afghanistan] and THEY [Al Qaeda] are THERE [not Afghanistan] aspect is absolutely essential in this conflict. If we are not allowed to pervasively enter Pakistan to engage Al Qaeda where they reside [at least in that region], then we are spinning our wheels in Afghanistan. Kinetically engaging transnational terror groups is akin to whack-a-mole as it is...if we consistently fail to even try to whack, then the entire process is an exercise in futility.
I desire as much if not more than the average person to engage and avenge Al Qaeda for the acts of 9/11. But reality has to trump vague idealism. We have to acknowledge that our actions both kinetic and non-kinetic, have distinct probabilities of creating more supporters of the Afghan insurgency, if not insurgents themselves. We have to realistically weigh the tangible threat posed by the various Taliban-esque [Quetta, Haqqani, HiG] groups with the desire to eliminate the entity that attacked us, meaning Al Qaeda. The media and two Administrations have diluted the discourse down to the point where the average American believes we're really taking it to the terrorists, when in fact we are mired fighting a sub-regional Islamic coalition that by and large merely wants their country back. Now, those Taliban elements are an anathema to our culture, but it appears to be a foregone conclusion by this point that we will be forced to either simply negotiate with them for a cessation of hostilities, or welcome them into a coalition government in Kabul. The ideological premise of merely withdrawing "without finishing the job" or some other such bumper sticker phrase, pales in comparison to again aligning with the people who were trying to kill you the previous day. [I say again, as we instituted the same paradigm in Iraq with the 1920 Brigade and other Sunni militia's].
Al Qaeda members have been targeted within the confines of Afghanistan over the last few years, but the number and scale of individual conflicts pales with those involving Taliban forces. Additionally, more Al Qaeda operatives have been engaged within Pakistan using cross-border deniable operations. But the number of AQ who have realistically been captured or [mostly] killed are not in any form of math, equal to the effort, resources and most importantly, lives that have been lost occupying Afghanistan. It's no stretch to state that the occupation, nor many of the tenets of a successful COIN campaign are not going so well.....after 10 years.