Andrew Gillum's remarkable victory in Florida's Democratic gubernatorial primary on Tuesday energized progressives and showed the Tallahassee mayor's ability to win over fellow party members thanks in part to a late endorsement from Sen. Bernie Sanders Bernie SandersThe Hill's Campaign Report: Trump faces backlash after not committing to peaceful transition of power Bernie Sanders: 'This is an election between Donald Trump and democracy' The Hill's 12:30 Report: Trump stokes fears over November election outcome MORE (I-Vt.).

But Gillum, 39, is likely to face a tougher general election battle in a state where President Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE remains more popular than in other swing states and one that hasn't elected a Democrat to the governor's mansion in decades.

Gillum will face off against Rep. Ron DeSantis Ron DeSantisTrump faces tricky choice on Supreme Court pick DeSantis wants to protect college students from punishment for not following COVID-19 rules Texas governor proposes stiffer penalties for organizing, participating in 'riots' MORE (R-Fla.), a Trump-backed conservative who has hitched himself closely to the president, pitting two populists from different sides of the political spectrum against one another in what many see as a proxy war between Trump and Sanders.

DeSantis, 39, has campaigned hard on the Trump agenda, but he has largely earned the support of his party, despite facing an intense backlash on Wednesday after warning Florida voters not to "monkey this up" by voting for Gillum.

ADVERTISEMENT

Gillum, by contrast, remains largely untested even within his own party despite winning city-wide races in Tallahassee for well over a decade.

The Democratic results were far from a blowout: Gillum prevailed in a crowded Democratic primary by winning 34.3 percent of the vote, edging out former Rep. Gwen Graham Gwendolyn GrahamModerate Democrats now in a race against the clock Dear Iowans: Apologies for Sen. Rick Scott's lack of decency Jimmy Buffett takes musical shots at Trump during concert MORE who got 31.3 percent. DeSantis, by contrast, blew out his Republican opponent by winning 56.5 percent of the vote.

That, according to some political observers, still leaves open the question of whether his progressive message, including “Medicare for all,” $15-an-hour minimum wage and legalizing marijuana can win over broader Democratic voters in November, let alone the general electorate.

Hillary Clinton Hillary Diane Rodham ClintonFox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio Trump, Biden court Black business owners in final election sprint The power of incumbency: How Trump is using the Oval Office to win reelection MORE captured more than 64 percent of the Democratic vote in Florida in 2016, while Sanders, who has emerged as a sort of patriarch of the progressive movement, took only about a third of the vote.

“Sanders hasn’t shown the ability to move voters in Florida,” one veteran Florida Democratic operative said recently. “I would struggle to truly, at this point, recall who the Bernie crowd was.”

Gillum also benefited in the primary from a below-the-radar campaign that saw him avoiding many of the attack ads that targeted his primary opponents like Graham (D-Fla.) or former Miami Beach Mayor Philip Levine, more-moderate Democrats who were widely considered the front-runners.

Gillum only revved up his campaign in the final weeks of the primary contest, launching his first TV ad of the cycle on July 25 — late in the game compared to his primary opponents.

He built momentum in the final stretch of the campaign by bringing in Sanders for two stops in Tampa and Orlando, and going on a statewide bus tour that included an appearance by former Housing and Urban Development Secretary Julián Castro.

But with the Democratic nomination now in his hands, Gillum is set to become the central target of DeSantis, a three-term congressman with wider national experience, who has played to Trump’s base of ultra-conservative voters with his frequent appearances on Fox News.

Also looming over Gillum’s campaign is an ongoing FBI investigation into Tallahassee City Hall over suspected corruption.

While Gillum has said he is not a target of the probe, several Tallahassee officials have been hit with subpoenas, including one demanding information on a business deal between the city and a lobbyist who was a former ally of Gillum.

Already on Wednesday, Gillum’s win triggered an attack from Trump, who tweeted that the Tallahassee mayor is a “dream” opponent for DeSantis.

“Not only did Congressman Ron DeSantis easily win the Republican Primary, but his opponent in November is his biggest dream....a failed Socialist Mayor named Andrew Gillum who has allowed crime & many other problems to flourish in his city,” Trump wrote. “This is not what Florida wants or needs!”

The Florida governor’s race is also certain to attract the attention — and money — of outside groups.

The Republican Governors Association (RGA) regularly outraises its Democratic counterpart, the Democratic Governors Association (DGA), and has no plans of yielding Florida to a Democrat.

None of these concerns do much to faze progressive Democrats who back Gillum, however.

Backers insist that Gillum's unabashedly progressive agenda will excite liberal voters in Florida enough to put a Democrat in the governor’s mansion for the first time since Lawton Chiles won reelection in 1994.

Gillum has vowed to campaign hard on a liberal agenda, calling for Trump's impeachment in an interview with CNN the day after his primary win.

Geoff Burgen, a spokesman for Gillum’s campaign, said Gillum’s progressive platform lends him a sort of authenticity in the state that will galvanize voters.

“I think voters want to hear about an authentic candidate,” Burgen said. “We’ve run on these issues. They’re issues that we think are a good North Star.”

Gillum also has big financial backers of his own. Democratic mega-donors Tom Steyer and George Soros have already poured millions of dollars into supporting Gillum’s bid, and the Collective PAC, a super PAC supporting black candidates, has spent more than $1 million on the race.

For his part, DeSantis has vulnerabilities of his own. He has based much of his campaign for governor on being a reliable backer of Trump's agenda, while name-checking the president often in television appearances and at campaign events.

That leaves open the possibility that he could push away more moderate voters and independents, who make up a sizable chunk of Florida's electorate, though he will likely retain the strong support of Republicans.

A Morning Consult poll shows Trump with a 50 percent approval rating in Florida as of July 2018, higher than the mid-40s shown in most national polls.

DeSantis also faced intense backlash after telling Fox News in an interview that “the last thing we need to do is monkey this up by trying to embrace a socialist agenda with huge tax increases and bankrupting the state.”

A campaign consultant working for Gillum slammed the comments as "blatantly racist." Meanwhile, Gillum — who would become Florida's first black governor if elected in November — tied DeSantis's comments to Trump's rhetoric while appearing on Fox News later in the day.

"It’s very clear that Mr. DeSantis is taking a page directly from the campaign manual of Donald Trump," Gillum said.

"In the handbook of Donald Trump they no longer do whistle calls, they’re now using full bullhorns," Gillum continued when pressed by Fox News's Shepard Smith about whether he believed the congressman's remarks were racist or just a figure of speech.

How much DeSantis's comments will hurt his campaign remains unclear. During his Fox News interview, Gillum reiterated that his campaign would continue to focus on his progressive agenda as his path to victory in November.

"What I’ve got to say about that is we got to make sure we stay focused, I think, on the issues that confront everyday people. I’m not going to get down in the gutter with DeSantis and Trump," he said.