In Georgia and Florida, young, African-American Democrats have a credible shot of winning governorships. In Texas, a charismatic, skateboarding Democratic candidate for Senate is speaking to overflow crowds, last week appearing at the largest single-candidate rally since the 2016 presidential campaign. Virginia reinforces its blue bona fides with each passing election, while Tennessee could elect a Democratic U.S. senator for the first time in 30 years.

The South has been like a political Mason-Dixon Line for the Democrats, who watched the demise of the conservative "Dixiecrat" in the '80s and have stood by helplessly as the GOP uses it as its own firewall in presidential elections. But a new kind of Southern Democrat is emerging, one who can attract younger voters and shake up the electoral map, experts say.

"The South as a sort of cohesive political unit may be fading," says Western Carolina University professor Chris Cooper, author with H. Gibbs Knotts of the 2017 book "The Resilience of Southern Identity: Why the South Still Matters in the Minds of Its People." The region is becoming more of a "two-South idea," with states like Alabama, Mississippi and Arkansas remaining solidly conservative, while the states long the Eastern Seaboard are providing openings for Democrats, he says.

Virginia, for example, has virtually established its identity as a blue state, largely because of young professionals in the area bordering Washington, D.C., and an influx of Latinos, says Seth McKee, a political science professor at Texas Tech University who has done extensive research on demographics and migration in the region. The Old Dominion – which voted in 2008 for a Democratic presidential nominee, Barack Obama, for the first time since Lyndon B. Johnson in 1964 – elected a Democratic governor last year and gave Democrats in the state House of Delegates their biggest pickup since 1899.

In Georgia, Democrat Stacey Abrams could become the nation's first black female governor, running neck and neck with GOP nominee Brian Kemp in the polls in her race. Florida Democratic nominee Andrew Gillum could become his state's first African-American governor as he battles Republican former Rep. Ron DeSantis for the governorship.

Tennessee Democrat Phil Bredesen, a former governor, is mounting a strong challenge to the GOP nominee, Rep. Marsha Blackburn, in a race that long would have been considered a Republican shoo-in. Louisiana and North Carolina elected Democratic governors in 2015 and 2016, respectively, while nine GOP-held U.S. House seats in the South are now considered toss-ups. In Texas, seven Democratic House challengers have out-raised their GOP opponents, six of whom are incumbents.

"It's not about changing hearts and minds. It's really about a changing electorate."

The most conservative Southern states, Alabama and Mississippi, remain largely out of reach for Democrats but are still on party activists' radar screens. Alabama elected a Democrat, Sen. Doug Jones, in a special election earlier this year after the GOP nominee, Roy Moore, was accused of sexual misconduct involving minors. Still, that race highlighted the power of female African-American voters who came out in droves for Jones.

In Mississippi, Democrat Mike Espy, a former Clinton administration Agriculture Secretary, is in a dead heat with the leading GOP candidate, incumbent Sen. Cindy Hyde-Smith, polls show. A more conservative Republican, Chris McDaniel, is running third. Experts expect there to be a runoff, and while Hyde-Smith is the favorite, Espy could have a chance if she were to slip to third and McDaniel captures the second spot.

McKee attributes the shift to changing demographics, with millennials – projected to soon be the biggest single generation – voting heavily Democratic, and Democrats of all ages moving to the South from other states.

"It's not about changing hearts and minds. It's really about a changing electorate," he says, calling it "the Obama coalition" making gradual inroads.

The current crop of Southern Democrats is more progressive than previous incarnations of the political beast. Unlike, for example, former Sen. Howell Heflin of Alabama (so conservative he was frequently pressed by the GOP to switch parties) or Sen. Zell Miller of Georgia, whose "D" identification didn't stop him from speaking at the 2004 Republican National Convention, the new Southern Democrats have a younger, hipper vibe.

The image can attract a certain kind of voter: Rep. Beto O'Rourke of Texas, who was once in a punk rock band, has an almost cult-like following and has moved Texas's U.S. Senate race to a stunning toss-up status. O'Rourke is challenging incumbent GOP Sen. Ted Cruz. Gillum has the support of progressives like Sen. Bernie Sanders of Vermont, while the charismatic Abrams has tapped into the support (and frustration) of women and minorities.

But the South may not be completely ready for a new era of Democrats, says Whit Ayres, a veteran GOP pollster. "It's not the Democratic Party our grandfathers knew. There's really no such thing as a conservative Democrat anymore," Ayres says.