PHILADELPHIA -- Six months into Hillary Clinton's presidential campaign, she met with a group of Black Lives Matter activists in Washington to make her case and seek their support.

DeRay Mckesson left disappointed, feeling Clinton lacked a grasp of the issues he had spent the previous year protesting in cities like Ferguson, Missouri, and Baltimore, including police brutality and income inequality. He came out of the October 2015 meeting unwilling to support her publicly.

On Wednesday, though, The Washington Post published an op-ed by Mckesson announcing his plans to vote for her after meeting again with her last week in Cleveland. He said he heard a candidate well-versed in the things that matter to him.

"There was no platform the first time," the 31-year-old Mckesson said in a telephone interview. "There is a platform now. I reflected on the things I've heard her say, commit to and seen in writing, and that's how I came to my decision."

A growing number of black millennials who were initially skeptical of Clinton -- questioning her commitment to end mass incarceration, confront racial bias in policing and repudiate her husband's tough policies on welfare and crime during the 1990s -- now support her.

Some do so enthusiastically, others pragmatically, because they find Donald Trump so repugnant with his talk of violence in "inner cities" and the need for "law and order."

But other activists are still not convinced that Clinton will address their priorities and are withholding their votes and public support as she makes a final push to enlist a group seen as key to her path to victory in November.

"It's a challenge and we're just facing it head-on," said Clinton aide Christopher Huntley, who focuses on millennials. He said the candidate is mounting a full-court press to reach young black voters and is being helped by "folks who have been skeptical now realizing and coming to that 'Aha!' moment that she's the best one to carry our water."

Clinton's platform includes establishing national guidelines on police use of force; police training in recognizing implicit bias; legislation to end racial profiling; increased funding for body cameras; sentencing reform; and federal aid to create jobs for young people, ex-convicts and small businesses in poor communities.

To help make her case to black voters, she has enlisted the Mothers of the Movement, a group of black women who have lost children to violence. They include the mothers of Trayvon Martin and Michael Brown. The mothers joined Clinton on the campaign trail in North Carolina last weekend.

Clinton is also reaching out to Black Lives Matter activists, several of whom have social media platforms that give them tremendous influence, and is campaigning at historically black colleges, deploying surrogates like New Jersey Sen. Cory Booker and tapping the likes of rapper Jay-Z to perform a get-out-the-vote concert.

On her 69th birthday on Wednesday, Clinton stopped by "The Breakfast Club," a popular urban radio show. Over the weekend, she tweeted a shout-out to historically black Howard University, which was celebrating its homecoming.

According to a new GenForward poll of Americans ages 18 to 30, 49 per cent of blacks say they will definitely vote in November. That's similar to the percentage of all young people. Eighty per cent of the likely black voters say they plan to cast their ballots for Clinton, versus 4 per cent for Trump.

Clinton has enjoyed strong support from older African-Americans, particularly in the South, where she defeated primary rival Bernie Sanders with 77 per cent of the overall black vote in states with exit polling. But in the GenForward poll, black millennials reported supporting Sanders over Clinton during the primary season 46 to 28 per cent.

In endorsing Clinton last week in an Elle magazine interview, Brittany Packnett -- a St. Louis organizer who was also at both Clinton meetings -- voiced some of the conflict felt by young black voters during the election season.

"These young people are understandably asking, 'What is the point of continuing to participate in this system that assaults me?"' Packnett said. "I have been wrestling with the same frustrations, but I have a responsibility to young people, to my community and to our work. The best way I can use my platform is to support Secretary Clinton."

Many black millennials had doubts about Clinton early in the campaign because of a 1996 speech in which she referred to young "super-predators" in the black community. She has since apologized for the remark.

In a heated moment on the campaign trail in April, Philadelphia activist Erica Mines confronted former President Bill Clinton about his support for welfare reform that activists say punished poor people and a crime bill that put many blacks behind bars.

Mines said she plans to vote for an independent next month.

"I do not believe she is someone who can be trusted," Mines said of Clinton. "She has been pushed because of Bernie Sanders to be more left than she has in the past. I do not trust her to do what is right for our communities. I only hear her talk about the middle class, which is not representative of those living at or below the poverty line."

Ferguson protester Johnetta Elzie said Clinton has done nothing to earn her endorsement. Elzie was among the protesters who met with Clinton in October 2015, but did not meet with her last week.

"There is no way I could promise to black people that she's not going to be horrible for us," she said. "That's not the hill I want my credibility to die on. I'm not going to guilt-trip people. I'm encouraging people to vote however you want on Nov. 8 -- or don't vote."