Democratic presidential nominee Hillary Clinton speaks to a voter during a voter registration event in Philadelphia on Aug. 16. (Melina Mara/The Washington Post)

The Clinton campaign says it is working to keep African American support for Donald Trump near zero, as the Republican nominee has begun urging black voters to abandon a Democratic Party that he says has done little to improve their lives.

Marlon Marshall, director of state campaigns and political outreach, said in an interview that “we do not take African American support for granted” and that the campaign has been expanding its outreach operation that helped Hillary Clinton win the Democratic presidential primary with the strong backing of black voters.

That effort included the use of large numbers of black elected officials, entertainers and grass-roots activists, who stumped for the former secretary of state in barbershops and beauty salons, in churches and on black college campuses and at rallies before large audiences of African Americans. Marshall described these surrogates and their testimonials on Clinton’s behalf as powerful tools that the Trump campaign cannot match. He also said that one of the campaign's "biggest surrogates, President Obama, will continue to campaign for the secretary as well."

“Since Day One, gaining the support and turning out African American voters has been a core focus of this campaign,” Marshall said.

Trump, following a reorganization of his campaign last week, has said he wants black people to vote for him, arguing that African Americans have little to show for decades of loyalty to Democrats. But his pitches have been made in front of largely white audiences, and the New York businessman has been criticized for describing the black community as locked in poverty, crumbling schools and violent neighborhoods. According to census data, the poverty rate for African Americans in 2014 was 26.2 percent.

“You’re living in your poverty, your schools are no good, you have no jobs, 58 percent of your youth is unemployed — what the hell do you have to lose?” Trump said Friday during a rally in Lansing, Mich., suburb where the population is more than 90 percent white.

Trump’s support among black voters is at historic lows for a Republican nominee, with polls in some key battleground states showing him near zero percent. In combined July and August Washington Post-ABC News polls, African American support for Trump was at 3 percent among registered voters. In the same surveys, 88 percent of African American voters reported an unfavorable view of Trump, including 77 percent who felt "strongly unfavorable," his most negative ratings among any demographic group in the survey.

By contract, Clinton polled at 91 percent among African Americans in the combined July and August surveys and was viewed favorably by 83 percent in the most recent poll.

Omarosa Manigault, a former contestant on Trump's reality TV show "The Apprentice," who is director of African American outreach for Trump's campaign, was contacted for this story. She requested a list of questions but did not respond.

Marshall said the Clinton-Kaine campaign staff is at least “30 percent diverse” and that more will be brought on board as the general election contest progresses. In addition to staff specifically assigned to mobilize black voters, such as Nadia Garnett, African American vote director, Marshall, who is African American, said campaign professionals of color are present in every department to ensure that the issues and sensibilities of voters of color are taken into account. For instance, the campaign’s policy director, Maya Harris, is a black woman, as is Karen Finney, the communications director for Clinton’s running mate, Tim Kaine. Amanda Renteria, national political director, is Hispanic.

Still, some black progressives were concerned when immediately after the convention, Clinton and Kaine set off on a bus tour through the Midwest that seemed to be aimed at courting white middle- and working-class voters.

Nina Turner, a top supporter for Vermont Sen. Bernie Sanders, was one of those who took note. “Democrats continue to fall back into their old habits of trying to court the white swing voter when that voter by and large is not going to be the demographic that pushes the Democrats to the top.”

Marshall noted that after the Midwest swing, Kaine addressed the Progressive National Baptist Convention. Clinton spoke to a joint conference of the National Association of Black Journalists and National Association of Hispanic Journalists in Washington and to the National Urban League in Baltimore, and last month  she addressed the NAACP’s national gathering in Cincinnati. Trump declined invitations to speak to all of those groups.

Clinton still struggles with a trust deficit among voters across the political spectrum, and much of the voter enthusiasm among voters of color that surrounded Obama's elections in 2008 and 2012 appears to have evaporated in 2016, said Steve Phillips, author of "Brown is the New White: How the Demographic Revolution Has Created a New American Majority."

As such, the Clinton campaign cannot assume that any group of voters will show up at the polls. Trump’s troubled campaign has left an opening for Clinton to make a play for white swing voters and Republicans who have said they will not vote for their party's presidential nominee. However, the way Philips sees things, that's not logical because math suggests that swing voters are not where Democrats trying to win the White House should focus.

Exit polling data from 1980 to 2014 shows that nonwhite voters — blacks, Asians and Latinos — are anywhere from 60 percent to 90-plus percent likely to vote for the Democrat in any presidential election. During that same period, white voters have remained nearly evenly divided between the major parties and have often leaned more heavily toward Republican presidential candidates. Over the course of multiple campaign cycles, Democratic Party candidates have not been very successful in the pursuit of white voters.

Phillips says this reality is the very reason that Democrats should invest far more heavily — with both campaign time and resources — in trying to energize black voters.

"Every additional black voter you turn out is 90 percent likely to vote for the Democrat. So, from an efficiency perspective, the time, energy and money spent trying to persuade one white swing voter who is at best only half the time likely to vote for the Democrat, well, that just makes far less sense. The upside is limited. The question really has to become how many people are they [Democrats] likely to really win with all this effort," Phillips said.

Even as national polls show Clinton pulling away from Trump, she needs to take care not to get complacent because of soft spots among some groups that came out strong for Obama in 2008 and 2012.

Jamal Simmons, a Democratic consultant, said that “black women over 40 appear to be mobilized and ready to go for Clinton, but are 18- to 35-year-old African Americans?”

“Bernie Sanders won over 70% of Millennials in the Democratic primary and polls show great interest by this cohort in third party candidates,” Simmons said via email. “Many of these voters are too young to remember when Ralph Nader helped cost Gore the 2000 election and may not care.”

The combined July and August Post surveys showed about a quarter of voters 18-to-29 choosing the tickets of Gary Johnson and Bill Weld (16 percent) or Jill Stein and Ajamu Baraka (9 percent) when they were became candidates. In the four-way contest, Clinton led Trump 43-25 among young voters in the combined July and August surveys, smaller than Obama’s 60-37 margin among young voters in 2012.

"We know we have work to do with millennials, and that’s why we have ramped-up our efforts in that area,” Marshall said. He added that the campaign is preparing to launch a tour of historically black colleges and universities and is emphasizing Clinton’s proposals for debt-free tuition, family leave and providing financial and black-owned small businesses as a way to engage younger black voters.

The campaign last month announced a drive to sign up 3 million new voters, and Marshall said that it has so far reached a third of its goal. Last week, Clinton attended a voter registration rally in a predominantly black neighborhood in Philadelphia, where she told the crowd, “Even though we’re doing fine right now, I’m not taking anybody, anywhere for granted.”

Scott Clement contributed to this report.