James Joyner at National Interest lays out why it really finally ought to be over for the U.S. in Afghanistan:

Following the murder of six NATO troops in yet another "green on blue" attack in which Afghan soldiers supposedly fighting on our side killed NATO troops, the coalition has all but ended combined operations with Afghan army and police forces at the tactical level, requiring general officer approval for exceptions. While spokesmen insisted that "we're not walking away" from the training and advisory mission that is the ostensible reason for continued Western presence in Afghanistan eleven years into the fight there, that statement rings hollow. As American Security Project Central and South Asia specialist Joshua Foust puts it, "The training mission is the foundation of the current strategy. Without that mission, the strategy collapses. The war is adrift, and it's hard to see how anyone can avoid a complete disaster at this point." Three years after doubling down on an unachievable mission, trust between NATO and Afghan forces is at an all-time low. Already this year, there have been thirty-six of these insider attacks,killing fifty-one NATO troops, most of them Americans…..

Joyner ends raising the interesting political question: why the heck isn't this debacle an issue in the presidential election? Well, because when it comes to foreign policy there's barely a drone's worth of difference between the two parties, of course.

My short interview with Michael Hastings, author of The Operators: The Wild and Terrifying Inside Story of America's War in Afghanistan, the story of our out-of-control Afghan military operation, from our June 2012 issue. Hastings told me:

But you sit down with McChrystal or any of the top guys who supported nation building and ask them: There's not popular support and there's not political support, and we don't speak the language, and Afghans don't want our culture for the most part, and the terrorists we are after are not there, and yet you propose we spend more billions and years? I will never understand that. I think the answer is more inertia-based thinking than rigorous intellectual analysis, because any such analysis involving Afghanistan would tell you to get the fuck out and not have anything to do with that country.

As I wrote back in February, "It's Never too Early to Finally Leave Afghanistan."