Defense Secretary Robert M. Gates approved a call-up of as many as 50,000 National Guard members to support security and relief efforts in the aftermath of Hurricane Gustav, which caused extensive damage to southern Louisiana after making landfall on Aug. 31. Guard troops were instrumental in enabling more than 17,000 citizens of New Orleans to evacuate before Gustav hit, and patrolled the city’s streets afterward to thwart looting and enforce mandatory curfews. Guard units are also poised to respond if Tropical Storm Hanna approaches the U.S. coastline. According to early predictions, Hanna could threaten the Eastern Seaboard between Florida and the Carolinas.