On Friday, U.S. Senator Rob Portman (R-Ohio), a member of the Senate Homeland Security and Governmental Affairs Committee, joined a group of senators in sending letters to Secretary of Defense Ashton Carter and the Chairman of the Joint Chiefs of Staff (CJCS) General Joseph F. Dunford, Jr. expressing concern over the Obama Administration’s recent release of Shaker Aamer from the detention facility at Guantanamo Bay.