John F. Tefft is a retired United States diplomat, and a Senior Fellow at the RAND Corporation.  He was a career Foreign Service Officer for more than 45 years, completing his service as the United States Ambassador to the Russian Federation from 2014 to 2017.  Tefft earlier served as the United States Ambassador to Lithuania from 2000 to 2003, Ambassador to Georgia from 2005 to 2009, and Ambassador to Ukraine from 2009 to 2013.  He worked from 2004 to 2005 as the Deputy Assistant Secretary of State for European and Eurasian Affairs responsible for U.S. relations with Russia, Ukraine, Belarus, and Moldova.