Sgt. John Hunt from Blackshear, Georgia, left, and Spc. Brian Kolessar from Middletown, New York, right, both from the 293rd Military Police Company out of Fort Stewart, Georgia, U.S. play jump rope with local children during a patrol in Kandahar City, so
Credit: Kirsty Wigglesworth / AP

Fernando Lujan, the special forces operative, peers from the rear window of a car as Kandahar Airfield slides past. It's a jarring scene.

In the past decade Kandahar has split into two worlds: inside the wire, and outside the wire. Inside the wire, there are taco nights, and big-screen televisions, and volleyball games, and wide roads with sensible speed limits, and Internet cafes – mile after mile, all surrounded by a ring of walls topped with razor wire and well-armed soldiers.

Outside the wire, there is only danger and death.

So as Lujan watches us pass the outer perimeter, he gives a half smile and says, "And there goes the wire." We're in a civilian car, wearing Afghan clothes and head scarves wrapped to obscure. Lujan slouches with a particular Afghan boredom as the car enters the desert. "Now we're in Afghanistan. The real Afghanistan." Sam, the civilian operator on Lujan's team, wears the grim but pleased look of a prison escapee. In the front seat, the Afghan driver smiles. We're on our way to Malajat.

Commanders throughout history have battled the wire, the bureaucratic isolation, struggling to interpret reports as they burble up through the ranks. Petraeus knows that. So in the face of an old problem he has reached for an old tool, developed before the technologies of drones, or satellites, or even radios, all the way back to Napoleon Bonaparte. The French general craved information and employed a tactic now called the "directed telescope," allowing him to peer through the fog and smoke of war. The telescope was a small team of brilliant young officers who operated without regard to rank, roamed across the battlefield, and then reported their findings directly to Napoleon. Good news or bad, he heard it in firsthand detail. And now, in Afghanistan, Petraeus has a directed telescope of his own: Lujan and his team.

As a human telescope – part of the Afghan Counterinsurgency Advisory and Assistance Team, or A-CAAT – Lujan sees the fullness of the war, from low-down gut shots on the battlefield to the strategies and pressures of command. On one day he'll teach basic English to Afghan fighters from far-flung provinces. The next he'll advise top strategists on the course of the entire war. Lujan arguably has a deeper understanding of the war – and counterinsurgency – than anyone else in Afghanistan.

Our car approaches a checkpoint manned by paramilitary guards with weapons. "We try not to stop," Lujan says. Better to avoid questions whenever possible. At the checkpoint's bottleneck, the Afghan driver gives a wide smile and a familiar, dismissive wave, as though to say, "No need for formalities among old friends." He keeps rolling through the checkpoint, betting correctly that the guards, wherever their loyalties lie, will not bother to shoot.

Lujan describes his job as a calling, and it is hard to imagine anyone more suited to it. He was born to a father he never met – an illegal Mexican immigrant who bailed out before his birth – and a mother incapable of caring for him alone.

He grew up among other relatives and their consorts, with no prospects for anything better. So he delivered a shock, one day as a teenager, when he announced that he had applied to, and been accepted by, the United States Military Academy. West Point, he told them.

He worked hard as a cadet. Then as a young soldier he became a Ranger, and then a member of the elite Special Forces, which led to missions around the world, including in Iraq. Then he returned to school – to Harvard, actually – for another degree and a better grasp of international affairs. He took a position teaching at West Point but soon grew disillusioned with academia; war had changed, but West Point hadn't. The academy taught America's young officers obedience, yes, but never prepared them for the flexible, fluid world of modern war. How could they learn to adapt, when even the number of inches between clothes hangers in their closets was dictated to them? Lujan felt called to do more – for his country, yes, but also for his students. So he volunteered for service in Afghanistan.

He still writes to his students, feeding them practical knowledge. "Insurgents have figured out how to make caveman-simple, pressure-plate or command-wire devices that all our technology is worthless against," he said in a long, heartfelt note a couple of months into his deployment. "We're seeing a reverse evolution in tactics, and they're deadly effective."

The note offers blistering, field-view insight into counterinsurgency, which military professors and philosophers could study as closely as any set of articles. "Every tiny piece of terrain out here exacts a terrible price," he wrote. "You just hope that commanders will learn quickly to pay only once. Don't clear what you can't hold. The Taliban will reclaim it before you finish walking or driving back to your base and lay IEDs along the way you came."

When Lujan left West Point, he published a paper that called for a revolution at the academy. It should stop manufacturing rule-memorizing bureaucrats, he said, and start fostering innovation. He lost friends and colleagues after that. His students heard his character questioned. So he ended his note from Afghanistan with an explanation of his decision. "Sometime in every single one of your military lives, you will face a moment where you see something that you deeply disagree with and believe needs to be addressed." When that day comes, he wrote, he hopes they'll break the rules. And accept the sacrifice that follows.

Now Lujan watches the Afghan landscape scroll past his car window, at ease wearing what lesser soldiers call "hajiflage." An assault rifle rattles at his knees and a sack of hand grenades sits at his feet. He has little interest in the debate among thinkers back home, on theories and traditions. He's a practician now. And he has more pressing matters at hand.