These things usually are. When the West, particularly the Americans, finally leave Afghanistan it's probably going to be messy - for a time. The Western presence in Afghanistan, military and civilian, has been enormous at least in Afghan terms. Neither effort, military or civilian, has been particularly successful but, when ended, both will leave a pretty big vacuum that others will seek to fill as others inevitably do when these opportunities arise.
Fortunately the past half century has given us numerous examples of Big (or lesser) Powers leaving small states. The Brits did it. So did the French and the Dutch. The Russians did it - a lot. Even the Americans did it in Vietnam. While the circumstances of each withdrawal varied enormously from the others, the wailing and gnashing of teeth in anticipation was almost uniform. It was usually cast as the end of the world, the Munchkins descending on their fellow Munchkins in an orgy of barbarism and chaos. Not that this didn't happen sometimes. Sure it did just not nearly as often as predicted.
Many times it turned out that civil strife followed our departure because of what we had done for our convenience when we ruled. Look at Africa, the Middle East and South Asia. Look at the borders. Look at all the straight lines. We drew those straight line borders as jurisdictional demarcation lines for the administrative convenience of the various colonizing powers.
Now consider those border enclosures as sort of corrals. Then look at what's been herded into those corrals. Inside we find groups of people of differing tribes, languages, ethnicity and religions. They just happened to be caught inside when we carved up their historic homelands with our straightedge borders. When they got uppity about it, we just put the boot in and maintained order at bayonet point.
Quite often we picked a submissive favourite to instal as the ruling clan. That's how Saddam's Sunnis got to dominate Iraq's Shia majority when that country was carved out of the Ottoman Empire by the Brits and French after WWI. But all good things must end and when we pack up our bayonets and go home, we leave behind us scores to be settled. Ask the Biafrans. Ask the Kurds or the Rwandans or the Congolese or the Balochs and Pashtun.
Afghanistan is about the most mixed up of the lot. For millenia it's been the meeting place of a lot of cultures, the pathway of conquering armies and marauders. Ethnically it's a hodgepodge of Persians, Orientals and South Asians. It's a herd of cats jammed inside borders that are often bureaucratic formalities. Pashtun, Tajik, Hazara, Uzbek, Baloch, Turkmen and more. Despite the centuries they haven't homogenized. A Tajik is still a Tajik, a Pashtun remains a Pashtun. Their shared values are usually reduced to distrust and resentment. That explains why truly effective central government has eluded them. The best they've ever managed was a loosely federated, highly decentralized state - an association of convenience of tribes that more or less accepted a Pashtun monarchy that wisely knew not to push its luck.
The thing is, we really haven't moved Afghanistan past Square One. We haven't settled the tribal issue, we haven't even tried. The ethnic warlords are still around and, right now, it's said they're busy reconstituting their militias in anticipation of our departure. We have babysat their unresolved civil war for more than a decade now but we haven't defused the conditions and circumstances that fueled it. What we must realize is that the resolution isn't going to happen while we remain there.
Those of us who've had the experience of teaching a child to ride a bicycle are familiar with the moment when the training wheels come off and you run alongside the child steadying the bike with a hand on the seat post until it's the moment of truth and you let go. You have to let go and stop and just stand there while you wait to see what happens. It doesn't always work out the first time but it usually does by the second or third try.
We're at that stage with Afghanistan. It's time to let go and see if they can ride their own bike. If the tribes can't rally behind a central government now, why would we think they will if we only stayed another ten or fifteen years? We keep saying it's a matter of giving them an adequate army and security force. No it's not. That's nonsense. No Afghan army can be any more valid or effective than the government it serves. If the government is too weak, too flawed to stand the army will simply devolve into constituent ethnic militias and return to the service of their tribal authority.
Leaving won't be a test of the Afghan National Army. It will be a test of the Afghan government, the executive and legislature in Kabul. The tribes must now decide whether they want central government. If they do they'll rally and find a form of government that works for all the tribes, including the Pashtun. If they don't they'll probably just resume the war we interrupted a decade ago perhaps this time as a proxy war between Pakistan and India. Either way we've stayed too long for the good we've done.