COMMANDER'S ADDRESS President Barack Obama thanks U.S. Sen. Dick Lugar of Indiana, center right, and former U.S. Sen. Sam Nunn of Georgia, center, for their work to help denuclearize countries after the fall of the Soviet Union at National Defense University in Washington D.C., Dec. 3, 2012. SHARE IMAGE: Download Image: Full Size (0.05 MB) Photo By: VIRIN: 337976-T-SXW78-844.jpg Photo Gallery