Lt. Col. John Nagl was at his peak.

It was 2007, the shimmery dawn of the group think experiment we now call the mass COIN (counterinsurgency) delusion. Nagl’s boss, Gen. David Petraeus, Washington’s newest demigod, had convinced everyone that his Surge Strategy could tame the wild disaster that had become the Iraq War. Nagl, who had positioned himself at Petraeus’s elbow to sell that formula, was now sitting in full dress uniform, his hair in regulation “high and tight,” whacking nimbly at the pathetic softballs lobbed by Jon Stewart who was being embarrassingly — and uncharacteristically — deferential to his decorated guest.

“It’s a very difficult kind of war, it’s a thinking person’s war, and it’s a kind of war we’re learning and adapting and getting better at fighting in the course of our wars in Iraq and Afghanistan,” Nagl pronounced in response to a question about FM 3-24, otherwise known as the “Counterinsurgency Manual,” which was written by committee led by Petreaus, “a remarkable man,” according to Nagl. FM 3-24 became the bible of COIN and the vehicle by which several of its authors, Nagl included, advanced their careers amid some very heady times — from 2007 through 2010 — in the Washington security world (I began sensing the decline as early as January 2010).

Iraq veteran and writer Carl Prine takes credit for calling them the COINdinistas first. They are the post-Bush civilian and military “crusaders” (as pegged by arch-COIN critic and TAC contributor Andrew Bacevich) dominating the Washington security establishment. Having gobbled down the fairy dust about the Iraq Surge signifying a new “graduate level,” “population-centric” counterinsurgency strategy (and ignoring our overwhelming firepower over Baghdad and Sunni strongholds and the complicated ethnic dynamics on the ground), they attempted to apply the same hocus-pocus to our war in Afghanistan under President Obama. FM 3-24 became more than a bible, but code for who was in and who was clearly out of the loop, infecting not only the think tank and beltway banditry, but the military agenda, too.

Then Tom Ricks, Washington Post correspondent-court scribe, conducted a full-blown high school popularity contest, literally ranking the “brains behind counterinsurgency’s rise from forgotten doctrine to the centerpiece of the world’s most powerful military.” In this cringe-worthy “top ten” published in Foreign Policy in December 2009, Ricks places “King David” Petraeus at Number 1, and then Nagl, whose Oxford dissertation-turned-Barnes-and-Noble-bestseller Learning to Eat Soup with a Knife made him a counterinsurgency “scholar,” among other bright lights of the time. Nagl, Ricks predicted, would be “in a top Pentagon slot within a year or two.”

That was just three years ago. Today, there is no better symbol for the dramatic failure of COIN, the fading of the COINdinistas and the loss that is U.S war policy in Afghanistan than this week’s news that Nagl is leaving Washington to be the headmaster of The Haverford School, a rich preparatory school (grades k-12) for boys on Philadelphia’s Main Line.

That’s right — Nagl, once called the Johnny Appleseed of COIN, who reveled in his role as face man, tutoring reporters with practiced bookish charm on the “the new way of war,”  and burnishing his personal story to convince everyone that he was a counter-insurgent before his time — a modern T.E. Lawrence — is packing up for good. Turns out that despite all the high hopes, the COINdinistas hit the brass ceiling with a smack, especially once it became clear that the magic they sold was a bag of beans. Among them is Michele Flournoy, who in 2007 founded The Center for a New American Security, the COIN-inspired, Democratically-charged think-tank which would become a feeder of the Obama administration. Flournoy was appointed Under Secretary for Defense Policy and the highest-ranking woman at the Pentagon in 2009. But not long after Obama appointed Leon Panetta — a career politician and bureaucrat, not a COINdinista — to Secretary of Defense, she left, citing family reasons. Her anticipated rise to Defense Secretary was thwarted as counterinsurgency efforts in Afghanistan, thanks to Commander Petraeus and COIN disciple Gen. Stanley McChrystal, became a huge albatross around the President’s neck.

It is easy to fixate on Nagl because he never seemed to enjoy debating the viability of COIN more than he did selling it, which just happened to coincide with his own professional trajectory. A dogged self-promoter, in 2004 The New York Times devoted a 9,500-word article to him, entitled “Professor Nagl’s War,” recounting his intellectual and battlefield exploits while serving as a battalion commander in Iraq. This resulted in some seriously squishy passages:

(Nagl) is like a paleontologist given the chance to go back in time and walk with the dinosaurs. But Nagl can’t simply stand around and take notes. He is responsible, with the rest of his battalion, for taming an insurgency, which is as difficult as teaching dinosaurs to dance.

By the time the insurgency in Iraq really hit the proverbial fan, Nagl was serving as a military assistant to then-Deputy Secretary of Defense Paul Wolfowitz. After helping write FM 3-24 ”under the stewardship” of Gen. Petraeus, Nagl’s profile soared as did the number of his media appearances. Subsequently, he was shuttled off to command a battalion of trainers and advisers at Ford Leavenworth, Kansas. In January 2008, the year Obama would win the White House, Nagl abruptly announced his retirement from the Army to seek a new career at Flournoy’s think tank,  so “I can contribute perhaps on a different level,” he told The Washington Post at the time.

He managed to curry sympathy with the mainstream national-security press, which blamed the Army for Nagl’s departure. “It’s another sign, more alarming than most, that the U.S. military is losing its allure for a growing number of its most creative young officers,” complained Slate’s Fred Kaplan, who pointed out for the millionth time that Nagl was a Rhodes Scholar and an Oxford graduate.

“Nagl, 41, has been one of the Army’s most outspoken officers in recent years. (This is a huge point against him, careerwise; the brass look askance at officers, especially those without stars, who draw attention to themselves),” Kaplan went on. Still, Kaplan says, “Nagl was precisely the sort of officer whose cultivation and promotion has been encouraged by the likes of General Petraeus and Secretary of Defense Robert Gates—a dedicated warfighter who also thinks strategically.” If that were the case, he couldn’t have been pushed out by the brass — we know Petraeus in his heyday saw to it that his disciples were promoted, not marginalized. There must have been something else going on.

But retirement allowed Nagl to parade his Golden Goose full time. And he did. In her brilliant 2008 profile, “The Cult of Counterinsurgency,” Tara McKelvey recalled her sit-down with Nagl on a summer morning in Washington:

The 42-year-old Rhodes scholar is armed with missionary zeal, an arsenal of quotations about military strategy, and Red Bull-ish energy on the conference circuit. He is constantly tapping his feet, twirling his pen, and slamming his hand on tables when he talks. (An admitted self-Googler, he is adept at self-promotion.)

Nagl has so successfully popularized counterinsurgency in the military and the general public that he is known as the doctrine’s Johnny Appleseed. One Pentagon insider says his achievements can be attributed “solely” to his ability to flirt. But, sitting at an outdoor patio table above Pennsylvania Avenue on a late summer morning, Nagl denies the charge. “I am shocked, shocked,” he says, jokingly explaining that he finds it “appalling and demeaning and absolutely untrue.” Then he leans back in his chair, takes off his glasses, and shakes his head slowly. “A man’s got to do what a man’s got to do,” he says.

After Nagl became president of CNAS in February 2009, it was clear that COIN was headed for woodshed, and fast. By 2011, even the CNAS white papers were subtly changing their tune about the viability of COIN in Afghanistan. McChrystal bombed out and was replaced by Petraeus, who managed to confuse everyone about the rules of engagement and his own expectations for Afghanistan before leaving the Army himself to become head of the CIA in the summer of 2011. A clear sign things weren’t going right was when Nagl left CNAS early this year to teach at the U.S. Naval Academy in Annapolis.

Perhaps this is what his future employers at Haverford meant when they praised ”his inspirational leadership and passion for educating future generations of boys and young men.”

While Nagl was pushing COIN, Obama surged tens of thousands more young men (practically boys) and women into Afghanistan. Many were killed, countless were maimed physically and psychologically. The FM 3-24 bible is now being rewritten because everyone feels free to acknowledge how lame it is. Even the most die-hard optimists now say the war is lost. How much the Afghans lost, and how much our Army lost as an institution from this painful diversion from reality, we’ll never know.

I asked Col. Gian Gentile — the West Point professor who put his career and reputation on the line by bucking the COIN mantra from its inception — what he thought about Nagl and the COINdinista legacy. Gentile was referred to as the “skunk at the Coin party” in Ricks’s now infamous “top ten” piece.

“I wonder often what has happened to all of the COIN advocates who had the volume cranked up to maximum levels just a couple of years ago with their arguments about savior generals transforming the wars in Iraq and Afghanistan,” he replied in an email yesterday.

“Now with American strategy in Afghanistan in tatters, where are their voices, where are … op-eds and articles claiming that since the savior general arrived the war has been made better? Do many of these folks not owe us an answer for the broken strategies that they helped to put into place?”

Sadly, with Petraeus at the CIA and McChrystal sitting atop his cushy perch at Yale, it does not appear that accountability is on the menu. But soup still is, and you can bet the rest of Washington has now figured out that it is easier to eat with a spoon.

Correction: Nagl was the S-3, operations officer for his battalion in Iraq. Later, he was a battalion commander in CONUS at Fort Riley, not Fort Leavenworth, as originally stated.