CHICAGO – Joe Biden and Pete Buttigieg have spent considerable energy trying to get back on track after stumbling on issues related to race.

Despite criticism from Sen. Kamala Harris and Sen. Cory Booker, the two African Americans in the Democratic race, Biden maintains the lead in support among black voters and is helped by his near-decade at the side of the nation's first black president.

Buttigieg has been criticized for his response after a police shooting that killed a black man in his community and even before that had little support from black voters. Buttigieg, who is gay, could face a challenge with older, more churchgoing black voters.

Biden spoke of his work with segregationist senators and got lambasted at last week’s debate by Harris for opposing federally mandated busing to integrate schools.

The former vice president pushed back that critics unfairly discount the entirety of his career on the issue of racial justice. Although Biden is the front-runner in most polls, he has seen his lead shrink.

Biden’s strongest support remains in the African American community where he is the choice of 36% of black voters for the Democratic nomination – the best of the nearly two dozen candidates vying to take on President Donald Trump, according to a CNN poll published Monday.

At last week's debate, Buttigieg acknowledged that he’s fallen short in diversifying his city’s police department. The mayor of South Bend, Indiana, and his small Midwest city are at the center of the latest flare-up in the debate on policing in America.

After the police shooting of Eric Logan last month, Buttigieg vowed to take action to improve the relationship in his city between police and the black community. He registered 0% support with black voters in the CNN poll after last week’s debate.

“I am asked how I’m going to earn the black vote in the polls 10 times more often than how my policies would benefit black Americans,” Buttigieg lamented in a speech Tuesday at the annual convention for Jesse Jackson’s Rainbow Push Coalition in Chicago. “It’s as if I’m being asked more about how to win than how to deserve to win."

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Biden, Buttigieg lose ground after debate

In the first-in-the-nation caucus state of Iowa, Biden's support remained steady at 24% in a post-debate poll conducted by Suffolk University and USA TODAY. That is the same level of support he had in a Des Moines Register/Mediacom/CNN Iowa Poll taken last month.

But in this week’s CNN national survey, Biden led the crowded Democratic field with 22% support – a 10-percentage-point drop in that poll since May. The former vice president saw his support dip 8 percentage points in a poll published Tuesday by Quinnipiac University. Biden holds a 22%-20% lead over Harris, a precipitous drop from the 11-point lead he held over Sen. Bernie Sanders, his closest rival three weeks ago.

In Iowa, a predominantly white electorate, Buttigieg came in fifth at 6% in the Suffolk/USA TODAY survey, compared with 14% in last month's Des Moines Register poll. In this week's CNN poll, he stood at 4% nationally among registered Democrats and Democratic-leaning voters, down 1 percentage point from the cable network's poll in late May. Buttigieg saw an even bigger decline in support in the Quinnipiac poll, where his support dropped to 4% compared with 8% in the university's last national polling June 11.

After the rocky debate performance, Biden defended his record and reminded voters of his ties to former President Barack Obama, the nation’s first African American president.

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"I moved to a state where there was still an ongoing, real, genuine struggle on segregation and rights related to the African American community,” Biden recalled at a Silicon Valley fundraiser Saturday about his move to Delaware from Pennsylvania as a child. “That's how I got involved as a kid in politics, and that's how I got involved as a public defender.”

At a speech before the Rainbow Push Coalition the day after the debate, Biden attempted to bat down Harris’ criticism on busing. He tried to downplay their debate tussle by arguing “that 30 to 60 seconds on a campaign debate exchange can't do justice to a lifetime committed to civil rights.” Biden was warmly received by the predominantly African American audience.

“You have to weigh the entirety of what the person has done over the course of his career," said Joe Nelson, 76, a retired Chicago Transit Authority worker. "I could be comfortable voting for him as president.” Nelson described himself as torn on whether to give Biden or Harris his vote in Illinois’ primary March 17.

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Buttigieg struggles to connect with black voters

Even before the police shooting that unsettled his city and forced him off the campaign trail for several days, Buttigieg struggled to win over black voters.

He rolled out what he dubbed the “Douglass Plan” – a proposal to increase economic prosperity in the African American community that was named after the abolitionist Frederick Douglass.

The plan includes changing credit scoring and increasing access to credit. He pledged that as president, he would increase the federal government's contracting with minority-owned firms to 25% and pass a new voting rights act that would ban voter ID laws and require potentially discriminatory voting law changes to be reviewed by the Justice Department.

Days after Buttigieg unveiled the Douglass Plan, Eric Logan, 54, was shot and killed by South Bend Police Sgt. Ryan O’Neill.

South Bend police said the officer was dispatched after reports of a man breaking into automobiles in the early morning hours of June 16. When O'Neill arrived, police said, he discovered Logan reaching into a car. O'Neill said that when he approached, Logan produced a knife and advanced on him in a threatening way. After several warnings, police said, O'Neill fired twice. He was wearing a body camera but did not turn it on during the encounter.

Buttigieg said before Tuesday’s speech at the Rainbow Push convention that his low standing in the polls with African Americans has more to do with the community’s lack of familiarity with him than the shooting.

“First of all, there are lot of voters I need to get to know and need to get to know me,“ Buttigieg said. “They need to understand the details of the Douglass Plan that we’re continuing to roll out, and frankly, they need to see me in action for a longer period of time.

"When you’re new on the scene and not from a community of color, you got to work much harder in order to earn that trust. Trust is a function largely of quantity of time.”

Rainbow Push convention attendee Jacqueline Carrera said Buttigieg was impressive, but many black voters “are risk-averse,” and that plays into their willingness to give Biden another shot and pass on Buttigieg.

“Black voters can’t risk to throw their votes on a candidate they think can (only) perhaps win,” said Carrera, who was undecided on whom to vote for. “So they say, ‘Joe has been there with us on this, and Joe has been with us on that.’ And, of course, his Obama connection carries so much weight. But they feel like they can’t throw their support on a candidate like (Buttigieg) because they feel they don’t know what’s going to happen to him. That’s the challenge for him.

"To me, this is an introduction for maybe another run for president or another office down the road.”

Jackson credits Buttigieg for handling awful situation with transparency

Jackson, who heads the Rainbow Push civil rights organization, said Buttigieg deserves credit for trying to find solutions for an issue wrapped up in systemic racism that has festered in South Bend and other communities

"He's handled an awful situation well by being transparent," Jackson said.

Other issues may be at play for Buttigieg as he tries to win support from black voters.

Sam Johnson, a Democratic operative in South Carolina, said Buttigieg struggles with older, churchgoing black voters from rural parts of his state in part because he is gay. South Carolina is the fourth state to vote in the 2020 primaries and has a Democratic electorate that is projected to be more than 60% African American. Winning black voters' support is crucial to winning the state.

Johnson, a former chief of staff to Columbia, South Carolina, Mayor Steve Benjamin, said Buttigieg needs to do more to drive his message to younger black voters, as well as those in South Carolina’s larger cities, who would be friendly to his message, if he’s going to turn his campaign around.

“Him saying he’s sorry is not going to get it done, but I think his message can resonate if he shows and tells how he’s going to make big change,” Johnson said.