Shawn Brimley is Special Assistant to the Under Secretary of Defense for Policy, Michelle Flournoy, in the Obama Administration. He and Flournoy previously worked at the Center for a New American Security (CNAS), where he held the 1LT Andrew J. Bacevich, Jr., USA Fellowship, from the Truman National Security Project. He was the 2007-2008 holder and inaugural recipient of the Fellowship, created in honor of the son of Andrew Bacevich, who was killed in action.
Before CNAS, he was a Research Associate in the International Security Program at the Center for Strategic and International Studies
Grand strategic view
He has written that the world strategic system is in a third evolutionary "turn". 
- shift away from a world of competing great powers before the Second World War toward a global environment defined by the contest between the United States and the Soviet Union (1945-1949) defining a bipolar world
- period between the fall of the Berlin Wall and the 1991 Gulf War constitutes the second turn, with the move to unipolarity
- slow and gradual shift from a unipolar to a complex multipolar world, with the U.S. losing dominance