ATLANTA (AP) — The South is where President Barack Obama and Democrats have long struggled. And it's where their party's toughest battleground will be in the fight this year for control of the U.S. Senate.

Democratic incumbents in North Carolina, Louisiana and Arkansas must face the consequences of having voted for Obama's health care law.

But first, Republicans must settle primaries in several states, including a challenge to Minority Leader Mitch McConnell of Kentucky.

All but one of the potentially competitive races is in a state Obama lost in 2012, and the president remains deeply unpopular among whites in the region.

Republicans are optimistic they can achieve the six-seat gain needed to retake the Senate.