Defense Briefing Defense Secretary Dr. Mark T. Esper and Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, brief reporters at the Pentagon, Sept. 20, 2019. SHARE IMAGE: Download Image: Full Size (2.49 MB) Tags: Chairman, Dunford, Defense Secretary, Esper Photo By: Lisa Ferdinando, DOD VIRIN: 190920-D-BN624-0129.JPG Photo Gallery