"We need the federal government to stay out of our way and let people help people and businesses create jobs," Allen said in a statement announcing his decision to run Tuesday morning. "Sadly John BarrowJohn Jenkins BarrowOur democracy can’t afford to cut legal aid services from the budget Dem files Ethics complaint on Benghazi panel Barrow thanks staff in farewell speech MORE believes in the centralized, bureaucratic model of big national government. That is out of touch with what works and out of touch with Georgia."

Barrow is the last white Democrat left in Congress from the Deep South, and Republicans hope they can finally knock him off in the heavily conservative district. But Barrow has shown time and again that he can win despite tough conditions. In 2012, he won by 8 points in a district Mitt Romney carried by 11 points.

Part of that win was due to a candidate some national GOP strategists said ran a lackluster campaign: Farmer Lee Anderson (R), who hasn't ruled out a potential comeback bid this election. Anderson did beat Allen in that race despite Allen's having spent more than $1 million in the primary and runoff to win.

John Stone, who Barrow beat by 30 points in 2008 in a district that was significantly more Democratic, is also in the race.

This post was updated at 3:20 p.m.