ATLANTA — Businessman David Perdue has defeated longtime Rep. Jack Kingston in the Republican runoff for Georgia's U.S. Senate nomination, setting up a nationally significant general election matchup against Democrat Michelle Nunn. Tuesday night's primary runoff win validates the former corporate CEO's campaign as an outsider. The former CEO of Reebok, Dollar General and the failed textile firm Pillowtex, Perdue offered his private sector record and tremendous wealth as proof that he can help solve the nation's ills in a Congress largely devoid of experience business titans.