What Price Victory in Afghanistan?

The downing of a Chinook helicopter carrying 31 Americans on Sunday graphically highlighted the continuing costs of fighting the war in Afghanistan. The presence of Navy SEALs among the dead made an emotional connection with the May killing of Osama bin Laden almost inevitable. The logic of that connection, though, has largely remained implicit: With bin Laden now dead, how long should the United States continue to accept the loss its very best in Afghanistan? Ending wars can be very difficult, even when the strategic ends of a war no longer justify the costs incurred. For the U.S. in Afghanistan, the question has become, at what point are the benefits of victory eclipsed by the costs of achieving that victory? In other words, would it make sense for the United States to "lose" the war in Afghanistan simply to put an end to the steady stream of casualties and the ongoing political and military investment in the survival of the Afghan government?