Associate Professor of Political Science Jeremy Weinstein has been named chief of staff to U.S. Ambassador to the United Nations Samantha Power, marking a return to government service for the former National Security Council staffer.

Weinstein will take a public service leave from Stanford to assume his new position, in which capacity he will advise Power on policy and advancing U.S. interests while also helping to manage the mission’s staff.

“Recent world events pose critical challenges to the United Nations, a global institution that reflects our shared commitment to promoting peace, security and human dignity,” Weinstein said. “I am honored to join Ambassador Power’s excellent team at this important moment for the United States and the world.”

Weinstein previously worked with Power from 2009 to 2011 on the National Security Council, where she served as senior director for multilateral affairs and human rights and he worked as director of development and democracy.