U.S. President Barack Obama (L) listens to Defense Secretary Chuck Hagel after the president announced Hagel’s resignation at the White House in Washington, November 24, 2014.

U.S. Secretary of Defense Chuck Hagel stepped down on Monday, after criticism of the campaigns in Afghanistan and against the Islamic State of Iraq and Syria (ISIS) militant group.

President Barack Obama announced Hagel’s resignation on Monday, saying the 68-year-old former senator and Vietnam war veteran had approached him last month to say it was time for him to leave. Hagel had been at his post for less than two years.

At a White House event in the State Dining Room, Obama and Vice President Joe Biden gave Hagel a warm sendoff.

He said Hagel has been candid with his advice and counsel and has “always given it to me straight.”

Obama said Hagel will stay on until a successor is confirmed by the Senate.

“The next couple of years will demand a different kind of focus,” an administration official said earlier, speaking on the condition of anonymity.

Hagel had raised questions about Obama’s strategy toward Syria in a two-page internal policy memo he wrote that leaked, Reuters reported. In it, he warned that Obama’s policy was in jeopardy due to its failure to clarify its intentions toward Syrian President Bashar al-Assad.

The White House did not give any clue who might be Hagel’s eventual replacement at the Pentagon, but the New York Times cited three candidates.

Former under-secretary of defense Michele Flournoy is said to be in the running, along with Senator Jack Reed of Rhode Island — a former army officer – and former deputy secretary of defense Ashton Carter.

Hagel, as a Republican senator, voted in favor of the 2003 U.S. invasion of Iraq, but later became a critic of the drawn out conflict that ensued and was taken on by Obama early last year to oversee the withdrawal of U.S. forces from Afghanistan.

Hagel’s experience as a non-commissioned officer who saw action in Vietnam was seen as a strength as he took on the job, but his public appearances have often appeared clumsy or underwhelming as the U.S. administration struggles to adapt to new conflicts.

 
[wpResize]