COLUMBUS — With a runoff increasingly likely in Georgia's tight gubernatorial race, Republican Gov. Nathan Deal is rallying his conservative base in north Georgia while Democrat Jason Carter is getting a boost from his grandfather, former President Jimmy Carter, who's appealing to black voters in some of the state's largest metro areas. The two campaigns are crisscrossing the state in the final days before the Nov. 4 election, holding rallies from Cornelia to Columbus.