Former Dean of Yale Law School Harold Koh is expected to leave his position as the State Department’s legal adviser to return to the Law School as a full-time professor in January 2013, the Wall Street Journal reported.

Koh, who was rumored in recent months to have been a potential candidate to succeed University President Richard Levin, was nominated to the State Department by President Barack Obama in March 2009. Previously, he had served as the 15th dean of the Law School after his appointment in 2004.

Within the Obama administration, Koh has been known for advocating Obama’s drone program against militants in Afghanistan and Pakistan, a position some have challenged as at odds with Koh’s record of criticism against former President George W. Bush’s legal approach to the war on terror.

“U.S. targeting practices, including lethal operations conducted with the use of unmanned aerial vehicles, comply with all applicable law, including the laws of war,” Koh said in a March 2010 speech, condoning the legality of targeted killing by aerial drone strikes in countries the U.S. government believes are dangerous.

Koh earned his law degree from Harvard Law School and is the Gerard C. and Bernice Latrobe Smith Professor of International Law at Yale Law School.