Andrew Exum writes a very valuable post hinging off the Tony Cordesman piece that I cited earlier, and the point of both posts is to test the tensile strength of the assumptions behind the Obama administration’s counterinsurgency strategy in Afghanistan. As a meta-point, it amuses me when critics accuse counterinsurgents of dogmatism or closed-mindedness. Ex is willing to subject himself to rather thorough self-criticism, as have many others in counterinsurgent circles — particularly around CNAS — who recognize that their course of action involves the escalation of a war. As far as I’ve concerned, from the perspective of intellectual honesty and intellectual rigor, they’ve acquitted themselves well. Personally, I would find arguments for de-escalation in Afghanistan more persuasive if they dealt similarly with an assessment of the risks they entail and why those risks ultimately better advance the national interest.

So to the substance of what Ex and Cordesman wrote. Rather than address each point, I think it might be more productive to start from their baseline, which is that the national interest in Afghanistan is not inexhaustible. (Steve Biddle, last year, called it a marginal call whether to escalate or muddle through.) Hearing Gen. Petraeus refer to it as “vital” in this morning’s Senate hearing (in fairness, he was citing language from President Obama’s West Point speech) raises the specter that we’ll pay any price and bear any burden to secure Afghanistan and protect it from backsliding into an area hospitable to the interlaced network of al-Qaeda affiliated insurgent groups. There has to be a way of expressing that there is a security interest in preventing that backsliding but not one that’s worth limitless war. “Important interest” maybe does the trick.

And so this debate becomes a judgment call about the margins of that interest. And here’s the point I really want to make, the one that I’ve been thinking over for the past couple of days: the American public has never debated, in a rigorous and bloodless way, just how proportional it is to confront a network of a few thousand extremists — this was Petraeus’s estimate during an exchange with Sen. Graham this morning — through a commitment of something upwards of $300 billion to date and roughly 100,000 troops. The damage that extremist network can export is real. But it’s increasingly insubstantial. If Umar Farouk Abdulmutallab, the perpetrator of the most sophisticated al-Qaeda plot in years, had succeeded, he would have killed an order of magnitude fewer people than on 9/11 — 300 people. Out of a nation of 300 million. And that is ultimately how asymmetrical warfare succeeds: what bin Laden calls “Bleed to Bankruptcy.”

Now, the reality is that bin Laden isn’t actually going to bleed the U.S. into bankruptcy. But what he can do is provoke the U.S. into counterproductive overreaction that’s beyond what we feel comfortable sustaining. And there’s more than enough evidence, when looking at the balance sheet, that he’s done that in Afghanistan. But that actually means we have the advantage. Because we can choose not to overreact, and we can choose to de-escalate, and put a campaign against al-Qaeda and its strategic depth (Haqqani, the Pakistani Taliban, the Quetta Shura Taliban, Hezb-e-Islami, al-Qaeda in the Islamic Maghreb/Iraq/Arabian Peninsula etc) on a sustainable footing. If the choice is between Going Big and Doing Nothing, both favor al-Qaeda.

But if the choice is to restrict al-Qaeda’s freedom of movement while combatting the strategic-depth network in Afghanistan; divesting ourselves of the responsibilities to secure Afghanistan; and bolstering the capabilities of our Afghan and Pakistani security-sector and governance-sector allies; then we’re getting somewhere. And these things are related: al-Qaeda would not be relying on the scrubs on the bench like Abdulmutallab and Faisal Shahzad if they were not feeling pressure.

And this is why, ultimately, I do think the strategy in Afghanistan/Pakistan makes sense. It’s a near-optimal balance of risks and benefits within the boundaries of a finite commitment. That is: the surge represents the best chance of rolling back years of Taliban advances in Afghanistan while giving the Afghan government a chance to actually govern and building a durable security sector, so that after July 2011, the Taliban is just less relevant to people’s lives — and, across the border, supporting and encouraging the Pakistani military to perform similar operations to restrict the space in which al-Qaeda and its strategic-depth groups operate. You move on that front by July 2011, and you can divest the direct-security commitment to Afghanistan pretty responsibly, and de-escalate the war accordingly, with a smaller contingent of U.S., Afghan and Pakistani forces that you’ll rely upon to essentially contain al-Qaeda forces in the border regions and Waziristan while they grow less relevant. And frankly, if you can’t do it in that time, you’ll have to deescalate anyway, because this sort of fighting and this sort of commitment is not sustainable.

Now: I am still advocating a mismatch of resources and interests. That, you can prudently respond, is not good strategy. And you’ll be right. Except for the fact that we live in a media and political climate where a plane that blows up and kills 300 people would prompt a political constituency for a massive reescalation in Afghanistan and probably an invasion of Yemen. That has to be confronted and defeated. Essentially, the American public needs to become more British or more Israeli (yes, I said it) in its understanding that some terrorism is just going to succeed and we need to find some sober, actuarial way of accepting that without constant freakouts. This is what keeps John Brennan up at night — resisting the pressures to overreact.

And that is a very difficult and very long-term task. We can’t take strategy-making out of the realm of politics in a democracy. I contend that the ultimate deescalation of the war into a state of Waziristan-based containment with fewer U.S. troops over a period of years will best balance all of these political problems and meet the Important Security Interest at stake. You go down after coming up. Surge, Deescalate and Sustain would be my approach. And it’s not significantly dissimilar to what the administration is doing. Is this a balance, and not an expansive statement of Interest or Non-Interest? Yes, and that’s the point.

Except here’s the thing. Both Petraeus and Flournoy kept talking about conditions on the ground guiding the deescalation post-July 2011. And in theory, that sounds great. But part of what has to be factored into those “conditions” is that the U.S. does not have a limitless interest in the war. If we’re at 68,000 troops — the pre-surge total — in July 2012, then we’re going to be overcommitting. Similarly, we should start recognizing that while we can’t tell just how much blowback you can generate from any given drone strike, they have some counterproductive radicalizing effect, or a similar effect of deepening an insurgent’s commitment to fight and maybe to export violence. The drone strikes are not a magic bullet. They’re a grenade, and their shrapnel can hit us.

Paul Pillar, a former senior intelligence official who spent a lot of time focusing on the Middle East, South Asia and al-Qaeda, said at the CNAS conference last week that his biggest piece of advice to President Obama on Afghanistan would be to make the July 2011 troop withdrawals meaningful and not cosmetic. That strikes me as prudent. Surge, Deescalate and Sustain.