Afghanistan is a country that spontaneously generates Taliban like the USA generates bowling leagues. Afghanistan is a country that produces most of the worlds opium (morphine) and depends heavily upon this form of produce. In case you’ve forgotten, heroin is acylated morphine. 

Afghanistan is a tribal confederation. The country has a very complex history of bloody invasion and occupation. Afghanistan is still gripped by fundamentalist religion and fierce tribalism- a fulminate and gunpowder combination. 

The USA exists as a democratic state today only as the result of a lengthy and self-imposed European evolution from medieval monarchy to democratic constitutional government over, say, 7-800 years from the signing of the Magna Carta to the US constitution. This is one metric. 

Afghanistan has not produced what the rest of the world would recognize as modern institutions and democratic ideals. Afghanistan did not produce a Magna Carta nor an intellectual renaissance producing steam power, electricity, metallurgy, or modern concepts of economics. In fact, much of Afghanistan outside of Kabul shows precious little interest in modernism of any sort.

So, the question is this- What do we hope to accomplish by our invasion of Afghanistan? Exterminate Al Qaeda? At its core, Al Qaeda is an idea. You cannot redirect intrenched ideas with an army.

Other than whack-a-mole military operations fighting insurgents who are armed by powers hostile to the US, we are left with trying to instill a sense of national identity by the installation of basic democratic ideals and institutions in what is little more than a tribal confederation. Afghans have no discernable history of gladly adopting western ideals. And the Afghans adhere to a religion that is poorly compatible with western ideals as well. How do US troops know if the bullets flying by are from the Taliban or from Al Qaeda guns? Just like Viet Nam, much of the indigenous population supports the insurgents either naturally or by coercion.

So, realistically, what does minimally acceptable success in Afghanistan look like? Would we recognize it if we saw it? How much residual Talibanism is acceptable to the occupying powers?