Race to choose Rep. John Barrow's challenger heads to runoff in Georgia's 12th

— -- A race in Georgia's highly competitive 12th District is headed for a runoff after no candidate won a majority in Tuesday's Republican primary.

The final field on Wednesday remained in flux.

State Rep. Lee Anderson received the top spot in the Aug. 21 runoff, but the Republican race was so close, it is yet unknown which Republican candidate finished second and earned the other runoff slot. Construction company owner Rick Allen finished just slightly ahead of Navy fighter pilot Wright McLeod-- who is backed by former district Rep. Max Burns--but his margin of victory was close enough to trigger a possible recount.

The Republicans are competing to take on Democratic Rep. John Barrow this fall. Barrow was first elected in 2004 and has been marked for defeat every cycle since then due to his unique position as a moderate, white Southern Democrat. This has made him the target of some severe redistricting challenges.

In 2006, Barrow saw his hometown of Athens cut out of his district and moved to Savannah. And then in this cycle, Savannah was cut from Barrow's district in addition to a portion of his Democratic base, making this one of the Republicans' top takeover targets in the country. The new district encompasses 19 counties.

This year in Congress, Barrow stands alone as the Deep South's last white House Democrat.

In other races, the contest for Georgia's newly drawn and open 9th District seat is also headed for a runoff after