MELISSA BLOCK, host:

Andrew Exum was one of many advisors to General McChrystal as he prepared his review of the war in Afghanistan. Exum is a former U.S. Army captain who led U.S. Army Rangers in both Iraq and Afghanistan. He's now with the Center for a New American Security. Welcome to the program.

Mr. ANDREW EXUM (Center for a New American Security): Thanks for having me.

BLOCK: Well, let's talk about what's not in this assessment today and that's the potential call for more U.S. troops. A skeptic would say, look, we've been in Afghanistan for eight years now. The Afghan army is nowhere near taking the lead. What's the best argument for the notion that more U.S. troops will make a difference in the numbers that we're talking about - doubling the size of Afghan security forces?

Mr. EXUM: I think the first thing that I would say is that I was there at the beginning of this war. I was there again in 2004. I went back this past summer, but I also fought in a place called Iraq. And Iraq was most certainly a drain on U.S. and allied resources for some pretty crucial years in Afghanistan. So, even though we've been there on the ground for quite a long time, as candidate Obama correctly noted in the run-up to the 2008 elections, we hadn't really tried to win in Afghanistan.

With respect to the Afghan national security forces, we know that we need to increase the troops to population ratio in Afghanistan to be successful from a counter-insurgency perspective. You can't do that only with U.S. and allied troops. So you're left with trying to grow the Afghan national army and the Afghan national police to supplement your own troop levels. And ideally, after, you know, 12 to 24 months, they should be the ones in the lead protecting the Afghan population, not the U.S. and its allies.

BLOCK: And does that seem realistic to you?

Mr. EXUM: I think it is realistic. I think that a realistic strategy for Afghanistan is that once - the good news is is that we'll be out of the lead in 24 months. The bad news is that I think we're looking at another three years of transition in Afghanistan and probably another five years after that in over-watch. So I think knowledgeable observers of the Afghanistan conflict look at a future engagement with Afghanistan and, you know, another decade of fighting.

BLOCK: You know, at the same time that we're talking about a buildup of U.S. troops in Afghanistan, we are at the end of a month that saw the highest number of U.S. casualties in Afghanistan since the war began, which is giving a lot of people pause about an escalation of this conflict.

Mr. EXUM: Absolutely. I don't want to seem callous, because, again, I've led U.S. soldiers into combat on three separate occasions. But I think that if you're looking for metrics to gauge U.S. and allied success or failure in Afghanistan, over the next year, violence is going to be a really bad metric.

As we put more soldiers on the ground in Afghanistan, as we increase our presence patrols, as we try to deny the Afghan population to the Taliban and the Hakani network and these groups that are waging a campaign of fear and intimidation against the Afghan people, violence is going to go up. The key metrics to look at are not so much how many U.S. and allied soldiers are killed, but how many fewer Afghan civilians are killed.

BLOCK: Isn't there, though, a troubling intersection of military and political goals here? In other words, the government of Hamid Karzai is widely seen as corrupt. We just saw Afghan elections where there were widespread accounts of fraud. People are asking what exactly is our U.S. military operation supporting there?

Mr. EXUM: Absolutely, I think that one of the ugly realities of Afghanistan or Iraq, as well, in 2007, 2008 is that our success depends largely on what our Afghan partners do and fail to do. And if that government in Afghanistan is seen as being less legitimate a year from now than they are today, it doesn't matter what we've done with respect to our own operations. We can still be facing down the barrel of mission failure in Afghanistan.

BLOCK: You say a year from now. What about right now? Members of Congress, the American people are going to be looking at things right now and saying: Why should we be sending more troops to Afghanistan given what we know right now?

Mr. EXUM: In Afghanistan, we've just put a new commander in place. We've just committed new civilian resources but I think that members of Congress and the American public need to know that additional brigades that are committed to Afghanistan, additional civilian resources that are committed to Afghanistan are likely not going to arrive until next spring.

It's too soon, I believe, to call the time on Afghanistan when we're just now starting to match our resources with strategic aims. But having said that, after 18 months, if we don't see any movement as far as building up key Afghan institutions, such as the security forces, as far as reducing Afghan civilian casualties, then I think that the public and their representatives have every right to start asking questions.

BLOCK: Andrew Exum, thank you very much.

Mr. EXUM: Thank you for having me.

BLOCK: Andrew Exum is a former army captain who served in Afghanistan and Iraq. He's now a senior fellow with the Center for a New American Security. Transcript provided by NPR, Copyright NPR.

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