Office Approach Acting Defense Secretary Richard V. Spencer walks to his office at the Pentagon, July 15, 2019, following the announcement of the nomination of Army Secretary Dr. Mark T. Esper to be defense secretary. Esper had been serving as acting defense secretary since June 24, 2019. Federal regulations require Esper to step down from that position during the review process. SHARE IMAGE: Download Image: Full Size (1.47 MB) Tags: spencer, acting defense secretary Photo By: Army Sgt. Amber I. Smith, DOD VIRIN: 190715-D-SV709-0014C.JPG Photo Gallery