On Oct. 7, 2001, the U.S. went to war in Afghanistan with the goal of routing al-Qaeda and the repressive Taliban regime in response to the 9/11 attacks. Victory appeared to come quickly and easily, and the Bush Administration's attention turned to Iraq. Then the Taliban regrouped. Ten years later, there are more than 100,000 American troops in the so-called graveyard of empires fighting a resilient Taliban and its allies, victory remains elusive and undefined, and the costs in dollars and lives keep rising. What are the lessons of Afghanistan and how should the U.S. play out the endgame as it prepares to withdraw its troops by the end of 2014? Time asked six respected commentators to weigh in.