But during a visit to the 30-acre campus in Lower Merion, Nagl (pronounced nog-gle), the current Minerva Research Fellow at the U.S. Naval Academy, said the stop in Haverford dovetails perfectly with his plans.
"I always hoped to have three phases to my life," the retired lieutenant colonel says. "First, the Army; second, service in Washington; and third, time in an institution of higher learning."
Nagl, a former Rhodes scholar with combat experience in Desert Storm and Iraqi Freedom, earned his doctorate in international relations from Oxford University in 1997.
His dissertation on counterinsurgency provided the kernel for both a book and a field manual he cowrote in 2005 to guide U.S. forces in Iraq and Afghanistan.
He advocated a messy, slow strategy - "like eating soup with a knife," a phrase he borrowed from Britain's T.E. Lawrence, or Lawrence of Arabia - in which U.S. soldiers mingled with, and supported, the indigenous population in an effort to undermine insurgents.
No more meeting the enemy head-on in battle, he said.
The strategy has come under fire after 42 fatal "insider" attacks in 2012 on U.S. and NATO soldiers from supposedly friendly forces in Afghanistan. The killings, Nagl said, are payback for U.S. officers' burning of the Quran.
In 2008, Nagl went to a Washington think tank and from there to the naval academy last January.
Soon, he will turn his attention to molding critical thinkers out of malleable schoolboys.
"I want to teach them to apply their talents most effectively in this world," he said. "That happens when what you do, and what you love, are the same. What can we do to make that overlap?"
It will be another year before the 1,000 students in prekindergarten through 12th grade get acquainted with this intense, animated man.
"He's a charismatic, outgoing personality," said Dr. Richard Abels, Nagl's boss at the Naval Academy and the school's history department chair. "I can see the midshipman [here] looking at him and saying, 'That's what I want to be when I grow up.' "
Incorporated in 1884, Haverford School has long catered to the Main Line's wealthy families, although it strives to be more inclusive.
Tuition ranges from $20,500 for pre-K boys to $33,500 for ninth through 12th graders. Because of the high cost, 28 percent of families receive financial aid, school spokewoman Dawn Blake said.
The school has produced famous figures like painter and illustrator Maxfield Parrish, Class of 1898, and Pete Conrad, Class of 1947, the third man to walk on the moon.
The school is carefully studying how best to nurture young men for productive lives. Departing headmaster Joseph T. Cox introduced programs on leadership, plus fostering a sense of compassion on campus, as a start.
The search committee that recruited Nagl has identified character development and educating "the whole boy" as keys to the new approach. Nagl is interested in that.
Kristin Lord, a former think-tank colleague of Nagl's, believes he's a gifted teacher and mentor.
"He ran and is still cultivating the next generation of security leaders," said Lord, of the Center for a New American Security.
Nagl, the oldest of six children from a Catholic family in Omaha, Neb., went to an all-boys academy and Jesuit high school as precursor to West Point.
At Haverford, he hopes to train boys for public roles, such as containing what he calls profligate spending in government. He'd like to prepare them for lives as fathers and husbands by introducing a coed course on marriage and the family.
"I'm not adverse to young ladies being present," he says. His own son, 10, will enter the school's fifth grade, and Nagl and his wife, Susanne, will likely stay to see him graduate. He hasn't said what will follow.
"If I know John, he will keep a hand in the policy world, write his op-ed pieces, keep up with contacts," said Abels. "I wouldn't be surprised if, a decade from now, you see John back in the public sphere."
Contact Bonnie L. Cook
at 610-313-8232 or email@example.com.