He was senior professional staff member for the House Armed Services Committee (1988-1992), assistant professor at Duke University (1992-1997); Deputy Assistant Secretary of Defense for Requirements, Plans, and Counterproliferation Policy (1997-2000); and Senior Vice President (2003-2007) and Vice President (2000-2003) at Hicks and Associates, Inc.
He then served as Senior Vice President and Director of Studies at the Center for a New American Security (2007-2009). Miller was confirmed by the U.S. Senate as the Deputy Under Secretary of Defense for Policy and as the Under Secretary of Defense for Policy.
On June 2, 2020, Miller resigned from the Defense Science Board in protest after police used pepper balls and smoke canisters to disperse protesters in the area surrounding Lafayette Park so that President Donald Trump, accompanied by U.S. Secretary of DefenseMark Esper, could attend a photo op at the St. John's Episcopal Church across from the White House.[11][12][13] In an open resignation letter to Esper, Miller cited the oath of office that he had taken to "support and defend the Constitution of the United States," and wrote that Esper and Trump had violated the same oath, writing:
President Trump’s actions Monday night violated his oath to “take care that the laws be faithfully executed,” as well as the First Amendment "right of the people peaceably to assemble." You may not have been able to stop President Trump from directing this appalling use of force, but you could have chosen to oppose it. Instead, you visibly supported it. Anyone who takes the oath of office must decide where he or she will draw the line: What are the things that they will refuse to do? Secretary Esper, you have served honorably for many years, in active and reserve military duty, as Secretary of the Army, and now as Secretary of Defense. You must have thought long and hard about where that line should be drawn. I must now ask: If last night's blatant violations do not cross the line for you, what will?[14]
Miller also criticized Esper's statement urging state governors to "dominate the battlespace," writing: "I cannot believe that you see the United States as a 'battlespace,' or that you believe our citizens must be 'dominated.' Such language sends an extremely dangerous signal."[12]
^ abJames Miller: Senior Fellow, Belfer Center for Science and International Affairs John F. Kennedy School of Government (last updated January 27, 2020).