Defense Testimony Defense Secretary Jim Mattis and Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, testify before the Senate Appropriations Committee in Washington, March 22, 2017. DoD photo by Navy Petty Officer 2nd Class Dominique A. Pineiro SHARE: Download: Full Size (2.16 MB) Credit: Dominique A. Pineiro VIRIN: 170322-D-PB383-008A.JPG Photo Gallery