(CNN) When Trayvon Martin, a 17-year-old black Florida high school student, was shot to death by a neighborhood watchman, African-Americans -- voters, bloggers, columnists, lawmakers, activists and academics -- wanted to hear from the nation's first black president.

It took President Barack Obama, who was running for re-election at the time, about a month to finally weigh in.

And when he did, his comments reflected his reticence to weigh in on an active investigation, but also his caution on matters of race.

"My main message is to the parents of Trayvon. You know, if I had a son, he'd look like Trayvon," Obama said, in his only reference at the time to the racial dynamics of the killing. "All of us as Americans are going to take this with the seriousness it deserves."

Obama's approach to race, at least as he was campaigning for white support, was predictable for much of his two terms -- tread lightly or, if possible, say nothing at all, to maintain the illusion of post-racial politics.

(The furor touched off by Obama's comment that Cambridge police "acted stupidly" in arresting a black Harvard professor at his home was a defining and instructive moment. Polls suggest his white support took a dip and never fully recovered in the summer of 2009.)

Obama's 2008 race speech was imbued with both-siderism. And his lectures to black audiences about their behavior assured whites that he wouldn't be captive to African-Americans as the first black president but instead would take a "tough love" approach.

But in 2018, the three African-American Democrats running for governor represent something of an evolution from Obama on matters of race. The candidates -- Georgia's Stacey Abrams, Florida's Andrew Gillum and Maryland's Ben Jealous -- speak to this post-Obama shift, which has been defined by the raw racial politics of Trumpism and the Black Lives Matter agenda.

Trump reportedly referred to African nations as "shithole countries." He suggested a moral equivalence between white supremacists and people protesting against white supremacists. And he has called NFL players protesting against police brutality "sons of bitches." In short, he has been a master of white identity politics, stoking white grievance by suggesting that his white base is under siege.

"You can't talk about people getting shot by cops and not talk about race. You can't talk about the President's comments and be kumbaya and expect people to take you seriously," said Andra Gillespie, an Emory University professor who has an upcoming book on Obama and what political scientists call "deracialization."

"This moment calls for a different approach. They have the same challenge of Obama, though, to prove that they are running to govern everybody and not just the black community," she said.

This new era hints at a post-post-racial era of American politics. Black politicians, courting white voters, are engaging in conversations about racism in a way that seemed politically perilous just a decade ago. Even as they take a somewhat bolder approach than Obama, all three black gubernatorial candidates are careful to say America's first black president faced different challenges that made his approach to race more complicated.

How they run

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On the stump in Florida, Tallahassee Mayor Gillum often turns to the story of Markeis McGlockton, who was shot and killed by a white man during an encounter over a handicap parking spot at a Florida convenience store.

But in his telling, Gillum, who says he would repeal the "Stand Your Ground" law if he becomes governor, likes to make the listener do some work, reversing the racial roles in the McGlockton killing.

What if a black man were yelling at a white woman sitting in the car with her two kids as her white partner went into the store? What if the black man then shot the white man who confronted him over yelling at his wife and kids?

"Could you imagine, just for a moment, if the shoes had been reversed?" he asked his audience a few weeks ago, as part of a Congressional Black Caucus panel featuring black gubernatorial candidates. "I'm not trying to be sensational about this, I'm just trying to speak the truth. We all know that race still matters in this society."

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The idea of "keeping it real" on race was echoed by Abrams, who's running at the top of the statewide ticket in Georgia. Often, that authenticity relies on biography.

At a recent rally in Clayton County, Abrams framed her stump speech with her experiences as a Spelman College student after the 1992 Rodney King verdict, where protests broke out across black America. The Atlanta power structure saw the protesters as "bad black people," she said.

She ended her standard stump speech, to a diverse audience, with a story from her teenage years, when, as valedictorian of her high school, her trip to the governor's mansion hit a snag.

"We walked up to the guard. He said, 'This is a private event. You don't belong here,' " she recalled, telling a story she tells at almost every stop.

The guard, she said, looked at the public bus her family traveled in "with a sneer." Eventually the guard let her family in.

The point of the campaign trail story -- which nods to race and class -- is that Abrams belonged in the governor's mansion as a teenager to celebrate her academic achievements and she belongs there now.

"Part of the responsibility is to have honest and authentic conversations about race," Abrams told CNN in an interview. "What we have to talk about is how race intersects with power. And my mission is to demonstrate that we can change the face of power, evolve it to include more people and people of different complexions and different backgrounds without diminishing anyone else's access to opportunity.

"But you can't do that when you ignore that race is part of the conversation."

Jealous, a former president of the NAACP, is running for governor in Maryland.

"I'm a black civil rights leader who has a white dad and a black son, so when I look at the issue of handguns, I'm urgently aware that black boys like my son are at extreme risk of homicide," he told CNN in an interview. "I have black cousins who have been shot in the last 10 years, and a white cousin who is in rehab. I am running with these labels."

While he is trailing in polls against Republican Gov. Larry Hogan, Jealous said he is "clear with folks that racism is a tool of wealthy special interests."

"The end effect of racism is we all lose," he said.