Hat to tip to WoTR for this challenging, short article 'Do We Know What We Are Doing in Afghanistan This Year? by MG Eric T. Olson and he asks:
So those who are looking for some understanding of how things are going and exactly what we are now doing in Afghanistan must search elsewhere. And to make sense of the critical decisions that will be made in 2016, such an understanding is essential.
Link:http://warontherocks.com/2016/01/do-...an-this-year/?

Personally I cannot see any US President - given the legacy of 9/11, the ejection of AQ from Afghanistan and simply still being there - in whatever format and number - leaving.