The Associated Press reports that "Ashton Carter, the Pentagon’s second-in-command, said Thursday he will step down in December, having served for two years under two secretaries of defense."
"In a written statement, Carter, 59, said he had long ago set December as his intended departure but delayed his announcement because of the government’s budget impasse."
“'I have decided that this situation might well continue and I don’t want any more time to pass before giving Defense Secretary Chuck Hagel a chance to search for a successor,' he wrote.'
"Hagel’s press secretary, George Little, dismissed any speculation that Carter was forced out. He said Carter’s decision to leave was his 'and his alone.'”
Secretary Hagel's statement can be found here.
U.S. Senator Lindsey Graham (R-South Carolina), a member of the Senate Armed Services Committee, released a statement saying, "It was with great sadness I learned Deputy Secretary of Defense Carter will be stepping down in December. He has been a steady, consistent and effective voice for our men and women in uniform. He also has great respect and admiration from senators on both sides of the aisle."