For much of her vice presidency, some of Harris' aides have thought she is too cautious in her public remarks. But when it came to Trump on Tuesday, she did not hold back.
She agreed with Charlamagne that Trump has embraced fascism and said his plans would make "it more difficult for working people to get by and to destroy our democracy." Republicans have accused Democrats of fomenting political violence, including the assassination attempts on Trump, by labeling him a threat to democracy. Trump, for his part, has repeatedly described Harris as a fascist.
On Tuesday, the vice president's comment was just one in a series of blunt attacks on his character and what he represents.
She also attacked him for admiring dictators, citing a report that he sent Russian President Vladimir Putin valuable COVID-19-testing equipment "when Black people were dying every day" from the pandemic.
"The man is really quite weak," Harris said. "He's weak. It's a sign of weakness that you want to please dictators and seek their flattery and favor."
She again condemned Trump for his role in the Capitol riot on Jan. 6, 2021, even as she shut down questions about whether the Justice Department had moved too slowly to prosecute him and whether he should be in jail in November.
"The court should handle that, and I'm going to handle November," she said.
Harris adopted a far different strategy to appeal to Black voters, specifically Black men, than former President Barack Obama used when he campaigned for her last week in Pittsburgh.
Responding to the wavering enthusiasm among some Black men that has caused panic in the Democratic Party, Obama scolded them and accused them of not "feeling the idea of having a woman as president."
On Tuesday, Charlamagne said Obama had been "finger-waving at Black men" and questioned when anti-Harris white voters would be admonished.
"What is happening is that we are all working on reminding people of what is at stake," Harris replied.
But she also acknowledged that she was not owed anyone's support.
"I need to earn every vote, which is why I'm here having this candid conversation with you and your listeners," she said.
She said that her child tax credit measure and investments in lowering prescription drug prices would help the Black community. She described a plan to provide 1 million loans that would forgive up to $20,000 for Black entrepreneurs. She said her economic agenda would increase "homeownership in the Black community."
And Harris said her goal to legalize marijuana would help Black men in particular. "I know exactly how those laws have been used to disproportionally impact certain populations and specifically Black men," she said, after brushing off a question about the false claim that she went out of her way to incarcerate Black men for marijuana offenses.
Charlamagne opened the interview by noting that Harris has been criticized for seeming "very scripted" and for sticking to her "talking points" in other media appearances.
"That would be called disciplined," she shot back.
The exchange set the tone for a lively and substantive discussion that featured prerecorded questions from listeners and others from people in the studio. Charlamagne was a generally friendly interviewer, suggesting that Trump should be "in prison" and interjecting with "that's right" when he agreed with the vice president. But he also pressed her on issues including the border and her record as prosecutor.
Harris did sometimes dodge and weave, including on a listener question that touched on whether she supported reparations for Black Americans over slavery.
"I say that as a preface to say two other things, and then I'll keep going," she said during a seven-minute answer, which dealt more broadly with her economic policy for Black Americans -- prompting Charlamagne to joke that she was filibustering.
("It has to be studied," she concluded on the reparations issue.)
One of the tensest points of the interview came when Charlamagne pushed Harris on one of her greatest political vulnerabilities: the U.S.-Mexico border.
She went on the defensive.
When the radio host asked whether President Joe Biden's administration should be blamed for the soaring number of illegal crossings recorded during most of his presidency, Harris repeated her standard argument that the White House had supported a bipartisan border security bill that would have sharply curtailed asylum. Republicans killed the bill after taking a cue from Trump, who did not want Democrats to secure an election-year victory.
But the exchange also included a rare comment from Harris about Trump's attempts to label her the "border czar." Biden did not assign her the job of managing policies at the border, but rather addressing poverty and corruption in Central America so that would-be migrants would stay home.
"If I responded to every name he called me, I wouldn't be focused on the things that actually helped the American people," Harris said of Trump.
Trump's immigration plans also came up when a caller asked about his proposal to invoke the Alien Enemies Act of 1798 to pursue summary deportations of suspected gang members.
"I have a sneaking suspicion that if Trump wins, he's going to use this law to put anyone that doesn't look white in camps, and I'm scared," the caller said.
Harris said that if Trump really cared about the issue, he wouldn't have torpedoed the bipartisan Senate border bill.
Trump tries to "instill fear around an issue where he actually could be part of a solution," Harris said. "He chose not to, because he prefers to run on a problem instead of fix a problem."
Harris does not often discuss the role of religion in her life or her identity as a Black woman, even after Trump sought to stir up racial divisions in July by falsely claiming that she only "became a Black person" recently.
On Tuesday the vice president was asked by a Detroit pastor about criticism, which he said came from the Trump campaign, that she was not engaged with the Black church.
Harris -- whose mother was Indian American and whose father is from Jamaica -- quickly dismissed that as "disinformation," saying that her opponents were trying to "disconnect me from the people I have worked with and that I am from."
"I grew up in the Black church. I grew up attending 23rd Avenue Church of God in Oakland, California," Harris said. "My pastor is Amos C. Brown of Third Baptist Church in San Francisco, California."
And she tried to turn the tables on Trump, who is not known for his faith and has a long history of making racist remarks, by suggesting he was a charlatan.
"He's selling $60 Bibles or tennis shoes and trying to play people as though that makes him more understanding of the Black community," she said. "Come on."