So, you’re saying just bring all the troops home and let the Taliban/AlQuada/Hamas, etc. have the whole of Afghanistan as their own unimpeded breeding/training ground for terrorists? The purpose of the engagement there is to weed those factions out before they come here. Not unlike the purpose in Iraq. The idea is to engage them on their turf rather than your own, because engage you they will.
They are already here. Haven’t you heard of the so-called “home-grown terrorists”? They are in mosques across America and on the internet and in our prisons. Afghanistan is just a small part. You have Pakistan, North Africa, Yemen, Lebanon, Iran, Syria. Do we go to war with all of them? How man soldiers have to die and be maimed for life before we realize islam is the problem, not a geographic location?