Undersecretary of Defense For Policy Christine Wormuth, whose tenure was marked by frequent clashes with the Senate on Iraq and Syria, will step down in June "to spend more time with her family," the Pentagon said Friday.
In a statement, Defense Secretary Ashton Carter said that "throughout her career, Christine has devoted herself to enhancing America's national security" in a variety of posts in seven years of service in the Obama administration.
"At the National Security Council and her many roles at the DoD, Christine has provided President Obama, my predecessors and me invaluable counsel on the nation's most challenging security issues," Carter said.
Carter said that Brian McKeon, Wormuth's main deputy, would replace her and serve as acting undersecretary of defense for policy. "With his depth of experience -- from Capitol Hill to the White House and now at the Defense Department -- and his expertise on the challenges the country faces, Brian will continue to serve DoD and the country well," Carter said.
Assistant Secretary of Defense for Asian and Pacific Security Affairs David Shear will assume McKeon's former duties as the principal deputy in the policy post, Carter said.
Wormuth, a former senior fellow at the Center for Strategic and International Studies, got off to a shaky start in her relations with the Senate at her February 2014 Senate Armed Services Committee confirmation hearing when she clashed with Sen. John McCain, an Arizona Republican and the committee's chairman.
McCain put a "hold" on Wormuth's nomination when he felt she was trying to dodge a question on whether al-Qaida's influence was expanding or being contained. She was not confirmed by the full Senate until June 2014.
Wormuth was also at the side of Army Gen. Lloyd Austin, who was then commander of U.S. Central Command, at the testy SASC hearing last September when Austin acknowledged that the $500 million program to train "moderate" Syrian fighters had only put "four or five" in the field against ISIS.
In trying to defend Austin, Wormuth said that the problem with the program was that the "moderate" Syrians wanted to fight the regime of President Bashar al-Assad more than they wanted to fight ISIS.
"There are many, many individuals in Syria who want to fight the regime," Wormuth said. "We were focused on identifying individuals who wanted to fight ISIL," another acronym for ISIS. "And that's a pretty challenging recruiting mission."