JACKSONVILLE, Fla. (AP) — The farther north you go in Florida, the saying goes, the deeper South you'll get. For generations, the Old South flourished in Duval County, a sprawling metropolis on the state's northern Atlantic coast that is home to Jacksonville and was once a reliable bastion of Republican power.

But when the Democratic gubernatorial candidate won the county two years ago, it energized Democrats and community activists aspiring to turn Jacksonville into another hub in the new, more Democratic South.

The race between President Donald Trump and Democrat Joe Biden will test that Democratic progress. Biden is counting on the county's sizable African American vote to do what no Democratic presidential candidate has done since Jimmy Carter: beat a Republican in Duval County and open another northern front in the contest for Florida's 29 electoral votes.

“Black voters in this part of the state are critical to winning statewide,” said Adrianne Shropshire, the executive director of BlackPAC. The national voter engagement project is sending more than 150 people to knock on doors in Black communities across Jacksonville.

While campaigns have traditionally focused on population centers farther south — Miami, Orlando and Tampa — Democrats can no longer afford to ignore the state's northern reaches, she said.

There's no doubt that strong Black voter turnout will be key for Biden.

Jacksonville, which largely shares its boundaries with the county because of their consolidated government, is home to nearly 1 million Floridians, nearly one-third of them Black. Democrats outnumber Republicans by nearly 40,000 registered voters in Duval County, and more than half of the county's Democrats are African American. But despite the advantage, the party's been held back by lower turnout.

Democrat Andrew Gillum, the state's first Black major party nominee for governor, bucked that trend two years ago when Democrats turned out in slightly greater numbers than Republicans. That was not the case when Hillary Clinton lost in Duval County to Trump in 2016.

Biden's campaign has been trying to build on the Democrats' 2018 effort. His running mate, California Sen. Kamala Harris, who would be the first Black vice president, held a rain-soaked car rally in town, after visiting a library where early voting was underway in a Black neighborhood.

When she visited Jacksonville earlier this month, Stacey Abrams, a former Democratic candidate for governor in neighboring Georgia, stood in front of a mural depicting the city's civil rights struggles to help get out the vote.

Democrats have been buoyed by the turnout among early voters. By Wednesday, 25,000 more Democrats than Republicans had already voted by mail or in person.

Republicans say they will close that gap with strong turnout on Election Day. The Trump campaign has poured its own resources into Duval County. Trump tried to hold his nominating convention in Jacksonville, until the virus forced him to cancel. Both Trump and Vice President Mike Pence, as well as two of the president’s sons, have made visits, before and after the coronavirus outbreak.

“The truth is the Democrats came and did the work. They worked hard. They registered voters," said Dean Black, chair of the Republican Party of Duval County. “And meanwhile, our local party had grown complacent and we didn’t have an organization that was doing the job that needed to be done. But we do now."

The area has also been a proving ground for Trump's attempt to peel off some Black voters — especially Black men — from Democrats. His campaign opened offices in one of the city’s predominantly African American neighborhoods. Online commercials feature African American supporters promoting the president's record, while former NFL great Herschel Walker has served as a surrogate on campaign spots. Some 6,000 Black voters in the county are registered Republicans.

Social justice activists like Michael Sampson, who founded the Jacksonville Community Action Committee, are wary of both sides — but especially of Trump.

“He’s been unrepentant in calling Black Lives Matter a terrorist organization ... and all these dog whistles to white supremacy," Sampson said during a recent visit to Friendship Fountain, which lies across the St. Johns River from the city’s gleaming skyline. The river cuts through the core of the city and serves as a dividing line between old and new, between the city’s mostly Black communities and more affluent white developments.

Sampson says the Black Lives Matter movement has sharpened Democratic voters' focus on the inequities that have long defined the community.

“All you knew was that Jacksonville was a racist big city, and it was never going to change — and that the good old boy system ran Jacksonville, and they will forever run Jacksonville,” said Sampson, who is Black.

“I think that calculus has changed,” he said, though he acknowledged that Jacksonville may still be decades behind Atlanta, Charlotte, North Carolina, and other rapidly changing cities of the former Confederacy.

Other people are more skeptical. Rodney Hurst, a longtime activist, said Jacksonville is “nowhere near where it could have been and should have been."

Hurst was 16 when a mob of white people began indiscriminately clubbing African Americans in downtown Jacksonville with baseball bats and ax handles 60 years ago on a day that is now remembered as Ax Handle Saturday.

Hurst, 76, says he doesn't think Jacksonville's leaders have “stood up and said we need to change this. So those who think it’s progress, I don’t.”

Still, many saw a watershed moment in 2013, when a coalition of activists demanded that the school board, after years of failed attempts, rename a high school that honored Nathan Bedford Forrest, a Confederate general and the first grand wizard of the Ku Klux Klan.

More recently, the city’s Republican mayor, Lenny Curry, has bucked some party orthodoxy by removing a statue of a Confederate soldier from atop a memorial in a park next to City Hall. He also put in place a mask mandate because of the COVID-19 outbreak. But Curry also has echoed Trump's attacks on the protesters who've called for change to fight racism in policing.

Black, the local GOP chair, acknowledged that Republicans can no longer take the county for granted, but he rejected the notion that Democrats would take over.

“We aren’t going to let that happen,” said Black, whose cattle farming family arrived in the area 10 generations ago, when the Spaniards still ruled.

But Florida Agriculture Commissioner Nikki Fried, the only Democrat to win a statewide office two years ago, sees Jacksonville as an area of opportunity for Democrats.

With more than 8 million votes cast statewide, she beat her Republican opponent by 6,753 votes. In Duval County, she won by a margin of fewer than 3,000 votes.

“You got to come,” she said during a visit to Jacksonville last week. “To understand our state, you come to Duval County.”