Here’s a pretty good article from American Affairs last year:

Data-Driven Defeat: Information versus Interests in Afghanistan
by Jacob Siegel

In the Spring of 2012, my battalion arrived in western Afghanistan as the Obama troop surge, meant to break the Taliban, drew to a close. The Taliban remained unbroken, but our new mission was training and assisting the Afghan security forces. Like all supposed changes in policy for Afghanistan, this one amounted to less than advertised. Our “train-and-assist” phase of the war coexisted with a decade of nation-building programs, counterterrorist operations, on­going counterinsurgency efforts, and assorted other State Department and government-backed nonprofit initiatives—which, together, pulled in many directions and arrived nowhere. The state of confusion ate at me for months until, finally, I had a eureka moment when we started getting orders to locate equipment left behind by other units and pack it off to shipping yards.

Then I understood: the generals’ metrics of success for the Afghan security forces we were assigned to train were only aspirational. The Afghans would never meet them; that was why we were leaving. …