WASHINGTON — Defense Secretary Ash Carter has given his top commanders the green light to allow more troops to carry weapons at U.S. bases, with a focus on recruiting stations, Reserve centers and other softer military targets. Carter’s actions came two weeks after a Kuwaiti-born gunman fatally shot four Marines and a sailor before police killed him at the Navy reserve center in Chattanooga, Tennessee. “The tragic shooting on July 16 in Chattanooga, Tennessee, illustrates the continuing threat to DOD personnel in the U.S.