U.S. Air Force Master Sgt. Justin Halterman 570th Contingency Response Group aerial transportation craftsman from Travis Air Force Base, Calif., guards the group command post during a firefight at Geronimo Landing Zone on Fort Polk, La., Oct 15, 2012. The CRG was supporting Joint Readiness Training Exercise Decisive Action. The exercise includes emphasis on joint forcible entry, phased deployment with an airborne parachute operation, a combined noncombatant evacuation, combine arms maneuver, wide area security, unconventional warfare and unified land operations in a joint, interagency, intergovernmental and multinational environment.