U.S. Marine Corps Lt. Col. Brian Greene, right, 2nd

U.S. Marine Corps Lt. Col. Brian Greene, right, 2nd Battalion, 4th Marine Regiment commanding officer, briefs Col. Kenneth Kassner, left, the commanding officer of 5th Marine Regiment, during Steel Knight 16 at Marine Corps Air-Ground Combat Center, Twentynine Palms, Calif., Dec. 10, 2015. Steel Knight enables 1st Marine Division to test and refine its command and control capabilities by acting as the headquarters element for a forward-deployed Marine Expeditionary Force. (U.S. Marine Corps Combat Camera photograph by ( Lance Cpl. Roderick L. Jacquote)/RELEASED)