Colonel (Ret.) Abigail Linnington, a Professor of Practice at the Fletcher School at Tufts University, has 25 years of service in the U.S. Army as a military strategist and aviator, retiring at the rank of Colonel. From 2016 to 2018, she served as a special assistant to the chairman of the Joint Chiefs of Staff and director of the Chairman’s Action Group. In this capacity, she provided support in the chairman’s role as a senior military advisor to the president, secretary of defense, the National Security Council, and Congress.