For the last week, Gregg Carlstrom has done an impressive job of highlighting all the reasons why U.S. observers should avoid chest-thumping over the wave of arrests of Taliban leaders by Pakistani authorities. Responding to a rather sanguine piece by Bruce Riedel in the Daily Beast on the benefits of this crackdown for the war effort in Afghanistan, Carlstrom has this to say:

On the Taliban arrests, there are two major theories about Pakistan's motives. One says Pakistan rounded up "moderate" Taliban leaders, those who favored reconciliation talks, so they would be replaced by a more "extremist" faction loyal to the ISI. The other argues that Pakistan plans to use the detained "moderates" as conduits back to the Taliban. (I guess there's a third theory, that the arrests stem more from Obama's diplomacy than Pakistani self-interests, but I find that dubious.)

Both of these theories are good for Pakistan. One is good for the United States. Neither is good for Afghanistan: In both scenarios, Afghan interests will be subjugated to Pakistani interests during reconciliation talks.

One of the main critiques of the previous administration’s Pakistan policy was that it paid little mind to understanding Pakistan’s motivations. This inattention allowed President Musharraf to play a double-game with the U.S., extending assurances that he was committed to routing the Taliban with one hand, while actively working against U.S. policy for the sake of Pakistan’s interests with the other.  It would be a shame if this administration forgot that lesson, all because Pakistan decided to arrest some militants for reasons that are a mystery to us.

That said, I think it's a mistake to look at Pakistan's possibly nefarious intentions and write off the possibility that its crackdown may yet accrue some long-term benefits to Afghanistan. After all, regardless of what you think about Pakistan's motivations, it's pretty safe to say that with these arrests, there has been a change in its behavior.  A tactical change, perhaps, but still a change.  There may yet be an opportunity here for the U.S. and Afghanistan to press that shift to their advantage.  Whether that's doable will depend on a range of factors.  Some of those are within our control. A great many more are not.  One thing you can say with confidence: failing to consider what drives Pakistan to act would, in all likelihood, doom any such effort from the start.