Homeland Security Secretary Jeh Johnson on Monday withdrew his name as a candidate to replace Defense Secretary Chuck Hagel.
Johnson, a former Pentagon general counsel, was a top contender for the position, but told the White House he was not interested in the job, according to the Associated Press.
Johnson joins a line of other contenders who say they don’t want to be considered for the position, after the president announced Hagel’s resignation last Monday.
Last week, frontrunner Michele Flournoy, former under secretary of defense, and Sens. Jack Reed (D-R.I.), and Carl Levin (D-Mich.) all said they did not want to be considered for the position.
Still on the list to replace Hagel is Ashton Carter, the former deputy defense secretary who left in 2013, and Robert Work, current deputy defense secretary and former Marine.
Hagel has said he will stay on until a successor is found, but Johnson’s recent decision highlights the difficulty the administration might have in finding a successor.
White House and Defense officials have publicly painted Hagel’s resignation as a mutual decision, but privately have said disagreements about policy played a role.