Afghanistan IS important. If the U.S. just leaves, the Taliban will come back into power. The Taliban and Al-Qaida are closely related, to the point where at times it can be hard to tell them apart.
If the Taliban regain power, we will again be treated to such spectacles as soccer stadiums being converted into execution centers for uppity women and anyone who doesn’t follow the radical Islamic path. It would be a huge propaganda victory for militant Islam. It would embolden the militants in Pakistan and help to destabilize that country. And it would deprive the U.S. of a staging area from which to go after al-Qaida.
That said, I still don’t see a path to ‘victory’ in Afghanistan. I’m not sure what a ‘surge’ accomplishes there. The ‘surge’ in Iraq wasn’t just a blind increase in manpower in the hope that it woudl help - the increase was done in support of a very specific counter-insurgency strategy that had defined tactics and defined goals. I don’t see anything of the sort in Afghanistan as of yet.
It may be that the role of the U.S. in Afghanistan is basically to be a permanent police force, much like the UN was in Cyprus or in parts of Africa. Rather than trying to ‘win’ the war, it may be better to just make sure that bases are well defended, and take a longer-term strategy of winning over the hearts and minds of the average person while building communication networks among the people to help root out al-Qaida and the Taliban. With no end in sight.