4-215. The Secretary of Defense approves SRUF, and the supported combatant commander incorporates them into plans and orders for various DSCA missions. The SRUF also apply to federal military forces performing a homeland defense mission on land within U.S. territory. They apply to federal military forces, civilians, and contractors performing law enforcement and security duties at all federal military installations (and while conducting official DOD security functions away from federal military installations), unless otherwise modified by the Secretary of Defense. This includes protection of critical U.S. infrastructure both on and off federal military installations, federal military support during a civil disturbance, and federal military cooperation with federal, state, and local civilian law enforcement agencies.