This guy gives 5 reasons to add troops in Afghan., but does not give ONE reason for why or how it will benefit the US. (Thats because its impossible to do so, but anyway...). We have spent untold trillions and many lives trying to make the rest of the world a democracy. If any country wants that - they'll do it.
Besides that fact...look at what we're doing with OUR democracy. Hmmm.
http://time.com/4789725/stavridis-afghanistan-nato/