If we haven't yet accomplished all we want in Afghanistan in the 16 years we've been there, then we never will. Its way past time to leave. 

I mean, c'mob...who isn't aware of the wisdom of the great Vizzini who 30 years ago said during a battle of wits, "You fell victim to one of the classic blunders—the most famous of which is, Never get involved in a land war in Asia"