ATLANTA (AP) — In the South, where a Republican sweep of Senate races would all but guarantee a GOP takeover of the chamber, Democrats are pinning their hopes on two coastal states whose economic and population growth have often outpaced their neighbors'.
North Carolina remains the Democrats' best bet for holding a hard-fought seat. And they see a long-shot chance to win Georgia's GOP-held seat growing slightly brighter.
But the Democrats' prospects seem grimmer in other Southern states.
They have virtually given up on ousting five-term Republican Sen. Mitch McConnell in Kentucky. And in Louisiana and Arkansas, veteran Democratic senators are struggling against challengers who relentlessly link them to an unpopular president, Barack Obama.
With Election Day less than three weeks away, all these races are being stirred by debates, spending shifts and visits by famous politicians.
In North Carolina, where Republicans are pouring millions of new dollars into trying to oust Democratic Sen. Kay Hagan, she spent Wednesday hitting GOP challenger Thom Tillis on women's health issues.
In Kentucky, Hillary Rodham Clinton's visit the same day came at an awkward moment. The Democrats' top Senate campaign group signaled Tuesday it would buy no more ads for Alison Lundergan Grimes' bid to defeat McConnell.
The most obvious difference in these races is the level of voter antagonism toward Obama. He lost North Carolina by only 2 percentage points in 2012 (after winning it in 2008), and he lost Georgia by 7 points.
But Obama lost Arkansas, Louisiana and Kentucky by far greater margins. Republicans in these states want to drive out the last of their statewide elected Democrats, much as Alabama and Mississippi did several years ago.
The South's political realignment — from conservative Democratic stronghold in the 1960s to "sunbelt" Republican ascendancy in the 1980s and 1990s — continues to evolve. Job growth in and around Atlanta and Charlotte and Raleigh-Durham, North Carolina, is helping Democrats compete in those regions, even as rural areas turn strongly against them.
"The East Coast South is diversifying economically and demographically much more than the inner South," said Ferrel Guillory, who tracks regional politics and trends from the University of North Carolina. Economically robust areas of Virginia, North Carolina and Georgia have seen a greater influx of jobs, Northerners and Midwesterners than have their Deep South neighbors to the west, he said.
Similar migration helped build Republican suburbs in the 1980s, Guillory said, but "now the growth is helping fuel Democrats," especially as significant numbers of blacks return to these states.
This year's Senate races in Kentucky and Georgia illustrate the trend. A year ago, Democrats held roughly equal hopes that one of the states would produce a net Senate gain. McConnell has never been deeply popular in Kentucky, they noted, and Georgia's seat was open thanks to GOP Sen. Saxby Chambliss' retirement.
But McConnell and his allies spent millions of dollars denouncing Grimes and Obama, and Grimes faltered recently when she repeatedly refused to say whether she had voted for the president.
In Georgia, both parties turned to non-Washington candidates. Democrats chose Michelle Nunn, daughter of former Sen. Sam Nunn, while business executive David Perdue survived a crowded Republican primary.
Georgia still tilts Republican, but Democrats are pounding Perdue for sending jobs overseas while heading large companies. They hope a libertarian candidate might force a Nunn-Perdue runoff in January, which would allow the attacks to continue.
Developments in key races:
LOUISIANA and ARKANSAS
Republicans used televised debates to tie Democratic Sens. Mary Landrieu of Louisiana and Mark Pryor of Arkansas as tightly to Obama as possible.
Arkansas Republican Rep. Tom Cotton used the term "Obama" or "Obamacare" nine times in his two-minute opening statement, 13 times in his two-minute closing, and nearly 50 times in between during a debate Monday.
"Clearly, Congressman Cotton is running against one man," Pryor said. "But I am running for 3 million Arkansans."
Cassidy used the same anti-Obama tactic in a debate with Landrieu.
Democrats note that requests for mail-in absentee ballots seem to favor them thus far, a possible sign of pro-Hagan enthusiasm. Republicans call the statistics insignificant, and say their targeted mail efforts will offset any Democratic edge.
In a state already saturated with political TV ads, the U.S. Chamber of Commerce is launching a new round, featuring Sen. Rand Paul of Kentucky praising Tillis.
The Democratic Senatorial Campaign Committee launched a $1 million TV ad buy that criticizes Perdue's comments on education. It's the committee's first direct spending for Nunn, who had hoped for more. In an accidentally leaked strategy memo, Nunn's consultants originally estimated an $8 million investment by the DSCC.
Still, her campaign claims momentum after a 2005 court deposition surfaced in which Perdue, the former CEO of Dollar General and Reebok, spoke about spending "most of my career" on outsourcing.
Clinton, the former secretary of state and possible 2016 presidential candidate, campaigned for Grimes in Louisville on Wednesday, one day after the DSCC stopped running TV ads in the race.
Grimes' supporters noted that she raised $4.9 million in the most recent quarter, leaving her more than $4 million to spend in the final three weeks.
"If Democrats are going to win this time, it's going to be won on the ground," said Will Carle, a Democratic political consultant in Kentucky.
Babington reported from Washington. Associated Press writers Bill Barrow in Atlanta, Adam Beam in Frankfort, Kentucky, Donna Cassata in New Orleans, and Gary Robertson in Raleigh, North Carolina, contributed to this report.