U.S. Army Gen. Martin E. Dempsey, left, chairman of the Joint Chiefs of Staff, welcomes Vice President Joe Biden to a conference with U.S. and U.K. senior military leaders at the National Defense University on Fort Lesley J. McNair in Washington, D.C., May 5, 2015. U.S. Army Gen. Martin E. Dempsey, left, chairman of the Joint Chiefs of Staff, welcomes Vice President Joe Biden to a conference with U.S. and U.K. senior military leaders at the National Defense University on Fort Lesley J. McNair in Washington, D.C., May 5, 2015. SHARE: Download: Full Size (0.35 MB) Tags: Photo Essays Credit: VIRIN: 341253-M-XVP89-840.jpg Photo Gallery