TALLAHASSEE — Since he declared for the Florida governor's race in March 2017, Tallahassee Mayor Andrew Gillum has stood out — for better or worse.

He trails the field of Democrats in fundraising, though he has often used it to tout that he is the only "non-millionaire" in the race, and has failed to completely distance himself from an FBI corruption probe into Tallahassee City Hall. He also continues to grapple with criticism of a political group that has funded an attack on rival and former U.S. Rep. Gwen Graham, though he said Tuesday that the group should disclose its donors.

But buoyed by this week's endorsement by billionaire philanthropist Tom Steyer, who pledged to support his campaign to the tune of $1 million, Gillum's team says he can still claim the nomination — by shoring up turnout of the African-American vote. It's a strategy that has narrowly propelled other progressive candidates across the country to primary victories. Gillum, the only prominent African-American candidate to run for governor in recent history, could gain from the same route.

"He's not trying to run a color-blind campaign," said Daniel Smith, a professor of political science at the University of Florida: "There's no question Andrew Gillum is running as a black man. He's not running away from that."

But is the attempt to boost black turnout enough to get Gillum to victory in a bellwether state?

"How much are we going to see that core regular black turnout grow?" Smith asked. "There's definitely room for it to grow."

African-Americans counted for about 29 percent of voters in the 2014 Democratic primary, said spokesman Geoff Burgan, mirroring a similar turnout rate in 2010.

"I think the mayor's path to victory heavily involves African-American voters, young voters, people who have typically dropped off" in other gubernatorial races, he said. "If that were to increase in '18, I would say that's a good thing for the state of Florida; that's a good thing for our campaign."

Read more: Financial disclosures show how Andrew Gillum faces an uphill battle in the race for governor

The Democratic Party in Florida has deep roots in the African-American electorate — which makes up about a quarter of the party's registered voters — even if the party's statewide candidates rarely come from its ranks. Aside from Graham, Gillum is also facing off against former Miami Beach mayor Philip Levine, Orlando businessman Chris King and Palm Beach real estate developer Jeff Greene.

Gillum's campaign is banking that explicitly highlighting his life experience and background, and running hard to the left, could appeal to voters who might not otherwise see themselves reflected in the field.

"We know what the definition of insanity is, right?" former Miami-Dade state Sen. Dwight Bullard said. "The Democrats have consistently picked what they presume to be the crossover candidate who could magically make the base excited and galvanize the swing voters they think they need to win the governor's mansion."

Bullard is now the political director for The New Florida Majority, a progressive organization focusing on helping marginalized communities build political power. His group endorsed Gillum, Bullard says, mainly because Gillum's message resonates with an increasingly racially diverse Democratic base.

Read more about groups that have endorsed Gillum here and here.

Although Gillum routinely reaches out to predominantly black audiences on platforms like drive time radio shows, the effect of such outreach is hard to gauge. His press releases have highlighted various appearances on such shows, where he has weighed in on issues like Kanye West's comments on slavery, and endorsements from media personalities like Charlamagne tha God, who hosts Power 105.1's "The Breakfast Club," which is syndicated in Florida.

Rep. Shevrin Jones, D-West Park, who is supporting the mayor's candidacy, said Gillum's work reaching out to African-American organizations and communities across the state seeds potential supporters who might not otherwise be measured by typical yardsticks such as polling of likely voters.

He cautioned that Gillum's outreach and appeal extends beyond those communities. Gillum has said his campaign path includes redder areas like the Villages and stops throughout the Panhandle. "Anyone who says that Andrew's campaign is only focusing on getting the black vote out is sadly mistaken," Jones said. "If you look at his supporters, the people who are behind them, a lot of them don't look like me."

But Jones acknowledged that Gillum's candidacy does strike a chord with many of the African-American voters in ways other candidates do not: "They're excited that we have this opportunity to have the first black governor, the opportunity to take over the Governor's mansion," he said. "People listen, people get on board, especially members of the African-American community."

Gillum has hardly shied from talking about race or class, calling for Confederate memorials to be removed and referring back often to his upbringing in Gainesville as the son of a bus driver and construction worker. On a campaign stop at the University of Tampa last year, he spoke with particular frankness about being black in his own city: "There isn't a day that doesn't go by in my city where I'm not driving behind a truck on my way to work that has a big old Confederate flag," he said at the time.

He added that he tries regularly to reassure himself "that they're not talking about me… that they don't mean me and I'm the mayor of this city, and all the other things that you tell yourself to be unpenetrated by the kind of inequality that you get to see and experience every single day that you live and breathe."

Recent history may provide evidence that supports Gillum's base turnout strategy, to a point. Kendrick Meek, perhaps the most recent prominent example of an African-American candidate seeking statewide office, won the Democratic primary for U.S. Senate in 2010 despite accusations of corruption leveled by Greene, who opposed him in that race.

Greene had sought to link Meek to Boston developer Dennis Stackhouse, who paid Meek's mother Carrie — herself a former U.S. Representative — in consulting fees and leased her a luxury SUV while seeking federal money for a project. Kendrick Meek lobbied for millions to fund the doomed venture, which never materialized, but said he was unaware that Stackhouse had paid his mother as a consultant.

Meek, in turn, bashed Greene for having made his wealth by speculating on the collapse of the mortgage market, and won the contentious primary despite Greene's spending millions on television ads against him.

"It didn't matter how much in the gutter that campaign went," said Smith, the UF professor. "There was a solid backing of African-Americans for Kendrick Meek."

But Meek, who eventually lost to Marco Rubio, also had the benefit of a wider platform as a U.S. Representative, and his mother was one of the first African-Americans elected to Congress. He was also contending against a general election field with much bigger names — former Gov. Charlie Crist running as an independent and Rubio, who had just finished his term as House Speaker.

Gillum, on the other hand, still struggles with name recognition in a race where about a third of the electorate remains undecided. Though Gillum has released digital ads, he is the only major candidate in the Democratic primary who's yet to start airing them on TV, another threshold for reaching voters.

He is also running against three candidates — King, Levine and Greene — who have poured millions of their own dollars into their campaigns. Graham, whose net worth is about $14.4 million, is the daughter of former governor and U.S. Senator Bob Graham and has better name recognition across the state. Most recent polling has Gillum in the middle of that pack.

Graham and Gillum's campaigns, in particular, have traded accusations of racism and sexism over a dustup last month sparked by Gillum supporter Leslie Wimes' comments calling the former North Florida congresswoman a "skank." The episode was further exacerbated by an ad attacking Graham funded by The Collective PAC, which describes itself as an organization to help "level the playing field" for candidates of color.

Read more: Who funds the group bankrolling this Democratic candidate for governor?

Both have also jockeyed to cast themselves as part of a national trend of progressive victories: Gillum and Graham have each intimated that they could be the next Stacey Abrams — the black woman who in May won the Democratic primary in the race to be Georgia's governor.

But the splintered Democratic field may be a boon for Gillum. Most of those voting for late-entrant Greene or King "are probably not going to be voting" for Gillum regardless, Smith noted. Gillum "doesn't have to peel off that much more. The winner could very much go through with less than 30 percent of the vote."

"If we go back to the 2014 primary election, there are going to be more than a million Democrats turning out in that primary election, considerably more. If you get 300,000 to 400,000 African-Americans to turn out to vote, it can make a difference," Smith added. "Are we going to have 500,000 African-Americans turn out in the Democratic primary? If so, I think Andrew Gillum sails to a win."

This post was updated Friday morning with the news of Tom Steyer's endorsement of Andrew Gillum.