But demographic changes and recent election results reveal a more nuanced landscape now as the two major parties prepare for their national conventions. Republicans will convene Aug. 27 in Florida, well established as a melting-pot battleground state, to nominate Mitt Romney of Massachusetts. Democrats will toast President Barack Obama the following week in North Carolina, the perfect example of a Southern electorate not so easily pigeonholed.

Obama won both states and Virginia four years ago, propelled by young voters, nonwhites and suburban independents. Virginia, long a two-party state in down-ballot races, had not sided with Democrats on the presidency since Lyndon Johnson in 1964. Jimmy Carter in 1976 had been the last Democratic nominee to win North Carolina. Each state is in play again, with Romney needing to reclaim Florida and at least one of the others to reach the White House.

Southern strategists and politicians say results will turn again this year on which party and candidates understand changing demographics and voter priorities.

“The transformation of the South seems to never end,” said Mo Elleithee, a Democratic campaign consultant with deep experience in Virginia and federal elections. “Now it’s beginning to emerge, at least parts of it, as solidly purple.”

New citizens, birth rates, and migration patterns of native-born Americans make high-growth areas less white, less conservative or both. There is increasing urban concentration in many areas. African-American families are moving back to the South after generations in Chicago, New York or other northern cities.

Young religious voters are less likely than their parents to align with Republicans on abortion and same-sex unions. Younger voters generally are up for grabs on fundamental questions like the role of the federal government in the marketplace.

“I wouldn’t say the South is any more ideologically rigid than anywhere else in the country. Certainly, it’s complicated,” said former Gov. Phil Bredesen of Tennessee. Bredesen, a Democrat, won twice while Republican George W. Bush occupied the White House. Before that, Bredesen was a two-term mayor of Nashville.

Republican Haley Barbour of Mississippi, a former national party chairman and two-term governor, said the demographics are important but can be overemphasized. He acknowledged GOP concerns that Hispanics will vote Obama in proportions Romney cannot overcome “if the election for them is only about immigration.” But, he added, “Never mind that their unemployment is so much higher than the national average. … If the election for them is about the economy, we can do well.”

Virginia grew from 7 million people to 8 million from 2000 to 2010, according to the census. North Carolina went from 8 million to 9.5 million. Both states were 65 percent white, a drop from 72 percent in each state. Native North Carolinians made up 58.6 percent of the population, a proportion that topped 70 percent two decades ago. Virginia is now half transient or immigrant.

“The North Carolina that Sen. (Jesse) Helms ran in was certainly different than today,” said GOP campaign strategist Brian Nick, referring to the cantankerous five-term Republican senator. Nick worked for Helms’ successor, Republican Elizabeth Dole.

Similar growth, migration and race trends are evident in Tennessee and Georgia, though they haven’t yielded the same party outcomes. In those states, white voters still break strongly for Republicans.

Republican Sen. Johnny Isakson of Georgia said “it would be dishonest” to argue race is not a prominent consideration in historical party identification, but he said race and demographics are not a primary driver in the state today. Isakson said it was new residents in metro Atlanta who helped the GOP take near total control of state government, with their votes based more on unseating entrenched powers than anything to do with social conservatism or old alliances based on race.

For decades after post-Civil War Reconstruction, the Lincoln Republicans were unwelcome in the South. Democratic loyalty intensified under Franklin Roosevelt and the New Deal. But the civil rights movement marked a split. “Dixiecrats” walked out of the 1948 nominating convention. In 1964, after Johnson signed the Civil Rights Act, Republican nominee Barry Goldwater’s margins in a handful of Deep South states looked like FDR’s three decades before.

From then until 2008, only Carter of Georgia and Bill Clinton of Arkansas managed Democratic victories in states that once belonged to the Confederacy. Both are native Southerners. Bredesen, a New York native, said he was called a “carpetbagger” in his earliest campaigns.

Heading into November, the former Confederate states have just five Democrats in the Senate and only a handful of white Democrats in the House. The GOP has a majority in one or both legislative chambers in all of those states except Arkansas.

There are outliers.

Kentucky re-elected a Democratic governor last year after sending tea party favorite Rand Paul to the Senate. While Republican presidential nominees rolled in North Carolina, Democrats Jim Hunt and Mike Easley were successful governors. Then, after Obama won the state, Republicans in their next cycle took both legislative chambers. Democratic Gov. Bev Perdue isn’t seeking re-election and Democrats could lose half of their U.S. House seats, including two vacated by incumbents.

In Virginia, counties outside metropolitan Washington, D.C., and along the Atlantic coast helped elect a succession of Democratic governors and U.S. senator and swung to Obama in 2008. Then they went solidly for Republican Bob McDonnell in the 2009 governor’s race.

The lesson, Nick and Elleithee said, is to know your audience.

Nick, the North Carolina Republican, said Democrats like Hunt and Easley talked effectively about education and maintained good relationships with the state’s banking, technology and research sectors. Now, he said, Republicans are learning to talk about “kitchen-table issues” and economic security, rather than leaning on social issues.

Elleithee, the Democratic consultant on Virginia races, noted the influence of federal contracting in driving the economy of northern Virginia, where votes often settle the statewide result. Debates over spending and the deficit play differently than in other parts of the country. “People hear a ‘cuts only’ approach and think, ‘that’s my job’ or ‘that’s my neighbor’s job,’” he said.

Bredesen, along with Rep. Heath Shuler, one of the North Carolina Democrats who isn’t running again, said even with advantageous demographic shifts, their party should still try to reclaim native white Southerners.

Shuler, a member of the Blue Dog caucus, said Southerners aren’t as divided as it sometimes appears. He lamented a hyper-partisan atmosphere in Congress that he said spills into party primaries that, in turn, yield extreme options for a general election. Given much of the region’s conservative bent, that dynamic has helped Republicans, he reasoned.

Nationally, Bredesen said, Democrats lost their connection with many small-town and rural whites because of a confluence of issues beyond race: Vietnam War protests, gun control, abortion, Supreme Court appointments, gay marriage. “I think the extent to which the national party has made a crusade out of some of these issues has driven people away,” he said. To connect with distinct urban, suburban and rural populations, Bredesen said, parties must “appreciate the whole diversity of experiences Americans have in this country.”

Barbour said Republicans should win over the growing nonwhite population based on policy. “The change in the South has been evolutionary, and I expect it to continue,” he said. “But people in demographic groups evolve, too. Besides African-Americans, who are pretty firm (for Democrats), most other groups ebb and flow.”