ATLANTA -- The South is where President Barack Obama and Democrats long have struggled, and it's where the party's toughest battleground will be this year in the fight for control of the U.S. Senate.
Three incumbents must face the consequences of having voted for Obama's health care law, but Republicans first 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 he remains deeply unpopular among whites in the region. Republicans are optimistic they can achieve the six-seat gain needed to retake the Senate.
Democratic Sens. Kay Hagan of North Carolina, Mary Landrieu of Louisiana and Mark Pryor of Arkansas are on the ballot for the first time since voting for the Affordable Care Act in 2010. The law's wobbly start and its image as a power-grab have the incumbents on the defensive, emphasizing local issues and avoiding unnecessary mention of the president.
Obama's Gallup job approval lingers in the low 40s, and is even lower in several states with pivotal Senate races.
A look at Senate races across the South:
n Arkansas sets up as a proxy for the tussle between the White House and House Republicans. Pryor, whose father served as governor and U.S. senator, is the last remaining Democrat in the state's Capitol Hill delegation. His Republican opponent, U.S. Rep. Tom Cotton, is a conservative favorite.
nIn Louisiana, Landrieu is seeking a fourth term never having topped 52.1 percent of the vote. She won twice in Democratic presidential years. She won in 2002, a midterm year, by running as a centrist who could work with a Republican White House.
n North Carolina voters give Obama a 43 percent job approval rating, and some surveys put Hagan's even lower.
North Carolina's House speaker, Thom Tillis is the national Republican favorite, but he must contend with several conservative challengers.
If Tillis emerges, Democrats plan to use his legislative agenda -- making it harder to vote, cutting public education financing and tightening abortion regulations -- against him.
--In West Virginia, U.S. Rep. Shelley Moore Capito avoided a bruising GOP primary, enabling her to build an organization and raise money for a race in an increasingly Republican state. Secretary of State Natalie Tennant will try to hold retiring Sen. Jay Rockefeller's seat for Democrats.
--In Virginia, Democratic Sen. Mark Warner is the most popular politician, and Obama won the commonwealth twice. But in Ed Gillespie, a former national GOP chairman, Republicans found a candidate who can raise the money to compete.
Follow Bill Barrow on Twitter @BillBarrowAP