NATO Meeting Acting Defense Secretary Dr. Mark T. Esper attends a meeting of NATO defense ministers at the alliance's headquarters in Brussels, June 27, 2019. SHARE IMAGE: Download Image: Full Size (2.72 MB) Tags: European Security, NATO, Partnerships, Mark T. Esper, Acting Defense Secretary Photo By: Lisa Ferdinando, DOD VIRIN: 190627-D-BN624-0025.JPG Photo Gallery