Ashton B. Carter offers remarks after President Barack Obama nominated Carter to serve as the next defense secretary during an event at the White House, Dec. 5, 2014. Obama's announcement followed the resignation of Chuck Hagel, who will remain in office until the U.S. Senate confirms a successor. Carter served as deputy defense secretary from October 2011 to December 2013, and served as undersecretary of defense for acquisition, technology and logistics before that.