I’m kidding, Ex. You can hold off on the aggrieved tweeting.

More seriously: Andrew Exum and David Barno have a valuable paper out urging an expiration date on U.S. counterinsurgency operations in Afghanistan. That’s October 2012, when the surge forces finally leave. After then, the U.S. should transition its mission to “security force assistance,” the fancy term for providing on-the-job training for the Afghan security forces. Put simply, in their view, the Afghans should be designing and conducting counterinsurgency operations, with U.S. combat forces and support units along for the mentoring ride. That’s necessity, Exum and Barno argue, for the Afghans to really prepare for 2015, when U.S. forces won’t secure their country anymore.

As I learned on a conference call this morning with both gentleman and a bunch of other reporters, there’s some disagreement about whether that means U.S.-led combat operations should stop after October 2012, and if so, how fast. That’s, I gather, what Ex means, since he fears giving commanders wiggle room to fight the war on their own will mean they give short shrift to active mentoring. Barno thinks that counterterrorism missions — like, for instance, the targeting of the Haqqani Network, though we can argue endlessly about that enemy-centric mission’s place within a counterinsurgency strategy — should probably stay a U.S. enterprise. And their boss, John Nagl, thinks that units in eastern Afghanistan ought to get another year to wage their war, because the east is a mess.

For what it’s worth, I’m sympathetic to Nagl’s view, but can’t really see why an extra 12 months would make a difference. I know John thinks that the east is an under-resourced theater from a counterinsurgency perspective, and he’s right. Why an under-resourced war will turn around in another 12 months of misery is hard for me to understand. More important is the Pakistani insurgent sanctuary across the border, which ain’t going away.

And that speaks to the value of the strategy CNAS offers. It’s as good a suggestion for how to get to 2014 as I’ve seen, and it raises the salient point that ISAF doesn’t currently encourage its commanders to provide on the job mentoring for Afghans even as it tries to work itself out of a job.

Also, twitter-snark from my friend Michael Cohen aside, the paper really ought to put to rest the canard that CNAS is blindly devoted to counterinsurgency in all circumstances. CNAS scholars, many of whom were practitioners of COIN themselves, considered it a least-worst-case-scenario for Iraq and Afghanistan. You’ll notice they didn’t call for its expansion to, say, Yemen or Somalia; and when its limits showed themselves in Afghanistan, they didn’t say that the facts have failed the theory or anything like that. Not many think tanks in Washington, on the right or the left, can say the same.

And for those who say COIN is dead, so everyone’s dumping the corpse: have you looked at Mexico lately? And have you considered that the Army’s having a freakout about its relevance and its budget? Counterinsurgency will never die, it’ll just mutate beyond all recognition, with nostalgia and memory and agenda and revisionism replacing history. You know, like punk rock.