John Nagl

In October of 2016, the Philadelphia Inquirer reported that according to court documents, Nagl had found marijuana in his son's backpack and, as punishment, had confiscated it along with the boy's cellphone. Two days later, he discovered the items missing from where he had hidden them, and found his son using the phone in a bathroom of the family home. When he attempted to take back the phone, the son refused to hand it over; as Nagl took the phone from his son's hands, the boy "re-engaged in a physical altercation" so Nagl "put his son in a choke hold to end the altercation quickly." Nagl's attorney, Robert Keller, told the Inquirer that "the facts showed that the parent took appropriate steps to discipline a child who was acting inappropriately" and that Nagl was "hoping to return [as headmaster] as quickly as possible." He was re-instated later that week, and has since continued his work as headmaster. On October 20, 2016, Delaware County, Pennsylvania, District Attorney John Whelan wrote in a one-paragraph statement that there was "insufficient evidence" to proceed with prosecution and that a charge against Nagl had being dropped.

Nagl was appointed as headmaster of The Haverford School in august of 2012.

In January 2011, he and CNAS chief executive officer Nathaniel Fick wrote an op-ed in the New York Times supporting the Obama administration's troop surge and reporting on its early successes. In April 2011, he wrote favorably about President Obama decision to name Leon Panetta, then director of the CIA, as Secretary of Defense, and General David Petraeus, then commander of the International Security Assistance Force in Afghanistan, with whom Nagl had worked on the new Army/Marine Corps counterinsurgency manual, as director of the CIA, noting the increasingly intertwined nature of the relationship between the intelligence and defense establishments in the United States.

After CNAS's founders, Kurt M. Campbell and Michèle Flournoy, left CNAS to serve in the Obama administration, Nagl was named CNAS's president in February 2009 and served until January 2012. Nagl remains a non-resident senior fellow of CNAS. While at CNAS, he co-authored several reports on a wide range of issues, including counterinsurgency, Islamist extremism and the future of the American military. While he was still in the Army, Nagl wrote a report in 2007 for CNAS which advocates for the creation of a permanent Army advisory corps, a proposal that he argued for in an op-ed in the New York Times. His proposal for an advisory corps was favorably cited by American historian Max Boot in a New York Times op-ed about ways to modernize the State Department and the American military.

Nagl served on the Defense Policy Board, which advises the Secretary of Defense, Deputy Secretary of Defense and Under Secretary of Defense for Policy. He is also a life member of the Council on Foreign Relations. He taught in the Security Studies Program at Georgetown University in 2009 and is a visiting professor in the war studies department at King's College London. In January 2012, he was named the inaugural Minerva Chair at the US Naval Academy, where he joined the history department at the Naval Academy and conducted research on the relationship between culture and warfare. He taught a course on the history of counterinsurgency to midshipmen at the Naval Academy.

Nagl retired from the Army and in 2008 became a fellow at the Center for a New American Security (CNAS) in Washington D.C.. Many commentators, including CNAS fellow Andrew Exum and retired Marine Colonel Thomas X. Hammes, lamented his retirement because they saw it as a significant loss for the Army. There was some speculation that Nagl retired because he had been passed over for promotion or otherwise sidelined by the military, as happened to H.R. McMaster, because of his advocacy of counterinsurgency, which had fallen out of favour with senior commanders by 2008. However, Exum confirmed on his Abu Muqawama blog that Nagl was not eligible for promotion to Colonel in 2008 and argued that Nagl could have greater influence on defense policy outside the military, particularly if he were given an opportunity to serve in the Department of Defense by a future administration.

Already notable in military circles, his public profile was further raised with an interview on Comedy Central's The Daily Show on August 2007. He was also interviewed with fellow counterinsurgency experts Lewis Sorley and Conrad Crane on the Charlie Rose show about the similarities between counterinsurgency during the Iraq and Vietnam Wars in March 2006.

After returning from Iraq, Nagl served as military assistant to Paul Wolfowitz, then Deputy Secretary of Defense, and Wolfowitz's successor, Gordon England, until 2006. While he was military assistant to Wolfowitz and England, Nagl co-authored the new United States Army and Marine Corps Counterinsurgency field manual as part of a team overseen by Generals David Petraeus, the former director of the Central Intelligence Agency, and James N. Mattis, the former commander of United States Central Command.

In 2006, Nagl was given command of the 1st Battalion, 34th Armor Regiment to help train Embedded Training Teams, small groups of American soldiers tasked to develop the Afghan National Army and Iraqi security forces.

Nagl later returned to Oxford to earn his DPhil at St Antony's College in 1997. At Oxford, his focus was on counterinsurgency. Nagl's doctoral dissertation was a comparative study of the British and American militaries as they dealt with insurgencies in Malaya and Vietnam, respectively. While at Oxford, he wrote several book reviews in a variety of military journals, focusing initially on the history of armored warfare, and later on the Vietnam War and guerilla warfare.

In 1997, Nagl was appointed as a social sciences professor at West Point. While teaching at West Point, he was affiliated with the Strategic Studies Institute at the United States Army War College for which he co-authored a book on military professionalism in 1999. He later received the George C. Marshall Award for being the top graduate of the US Army Command and General Staff College in 2001. A revised version of his dissertation was published in 2002 as Learning to Eat Soup with a Knife, titled after an observation made by T. E. Lawrence about the challenges of fighting guerilla forces. He served as Deputy Chief of Staff for Operations and Plans for the 24th Infantry Division at Fort Riley, Kansas. Nagl deployed to Iraq in 2003 as the operations officer of the 1st Battalion, 34th Armor Regiment, 1st Infantry Division stationed near Khaldiya. While in Iraq, he was profiled in the New York Times Magazine in January 2004.

Nagl was raised in Omaha, Nebraska, where he graduated from Creighton Preparatory School in 1984. He then attended the United States Military Academy at West Point, where he studied international relations and graduated near the top of his class in 1988. As a newly commissioned second lieutenant, he was chosen as a Rhodes Scholar and studied international relations at St John's College, Oxford, earning his MPhil in 1990.

John A. Nagl (born 1966) is a retired Lieutenant Colonel in the United States Army. He is former president of the Center for a New American Security and current headmaster of The Haverford School. Nagl is an expert in counterinsurgency and has published two books on military strategy.