National security question trips up Sen. Darline Graham in South Carolina debate AP NewsDarline Graham defends her résumé in South Carolina debate after saying ‘national security is not my thing’ NBC NewsEarly voting for GOP U.S. Senate runoff begins WCIVLindsey Graham’s sister and fill-in senator says she’s ‘not that informed on national security’ The GuardianDarline Graham says she's "not that informed on national security" at debate CBS News