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: Download: Full Size (2.72 MB) Tags: nato, partnerships, european security, mark t. esper, acting defense secretary Credit: Lisa Ferdinando, DOD VIRIN: 190627-D-BN624-0025.JPG Photo Gallery