From NGAUS:
With the resignation of Defense Secretary Chuck Hagel Monday, speculation is growing about who President Barack Obama might nominate to replace him. It is doubtful that a new defense secretary will be confirmed by the Senate by the end of the year, but here are some names that have popped up in news stories since the resignation was announced.
Ash Carter: Carter has served at the Pentagon in the No. 2 and No. 3 jobs so he is well known in Washington, D.C., and the Pentagon. He was Pentagon’s top weapons buyer from 2009 to 2011 and then was deputy defense secretary until last year. A candidate for the post when Hagel was selected, he is now with a private philanthropic organization.
Michele Flournoy: The founder and head of a Washington, D.C., think tank, the Center for New American Security, she served as the under defense secretary for policy from 2009 to 2013. She is described as a Democrat and has written about the need for bipartisanship when it comes to national security. A woman has never led the Pentagon.
Air Force Secretary Deborah Lee James: James served as the assistant defense secretary for reserve affairs during the administration of President Bill Clinton. She was a staffer on the House Armed Services Committee and has received high marks in her current position.
Sen.Tim Kaine: A Democrat serving on the Senate Armed Services Committee, he was an early supporter of the president’s fight against the Islamic State, but more recently has called the war illegal.
Deputy Defense Secretary Robert Work: A former Marine, he has served as the under secretary of the Navy in the Obama administration.