[1] He was formerly senior adviser with the Center for Strategic & International Studies in Washington, D.C., and the third United States Ambassador to Ukraine from 1998 to 2000.

[2] He served at the United States Embassies in Warsaw, London and Moscow, and as advisor on the U.S. delegation to the negotiations on intermediate-range nuclear forces in Geneva.

[3] From 1996 to 1997, he served special assistant to the president and senior director for Russia, Ukraine and Eurasia on the National Security Council.

From 2001 to 2004, he served as deputy assistant secretary of state in the Bureau of European and Eurasian Affairs, with responsibility for Russia and Ukraine.

"[4] Pifer is author of "The Opportunity: Next Steps in Reducing Nuclear Arms" with Michael E.