Both were honored last fall with the National Civil Rights Museum’s Freedom Award and had kind words for each other during the ceremony . Biden glossed over their past and described their experiences on the campaign trail together as pleasant.

Biden’s campaign declined a request to interview the former vice president for this story and did not offer further comment on the record. But there are signs Biden has made efforts to mend their relationship.

And Biden mentioned Jackson several times during his speech to party officials, observing at one point that Americans are “more together on what we should be doing as a nation in terms of issues than they were when Jesse and I were getting started.”

The Rainbow Coalition founder has grown into an elder statesperson’s role in the party and remains influential, sometimes for sentimental reasons. His 1988 campaign has been pegged as a gateway to organized Democratic politics for Sen. Bernie Sanders, at the time the socialist mayor of Burlington, Vermont, and now one of Biden’s top competitors for the 2020 nomination. Candidates were also eager to show their admiration for Jackson during last week’s DNC gathering. On Instagram, Beto O’Rourke, whose father chaired Jackson’s Texas campaigns, posted two photos: one of himself as a preteen with Jackson in 1984, and another of him shaking hands with Jackson in Atlanta.

And Jackson nodded when asked if he remembered how Biden treated him ahead of 1988.

Jackson added that he fundamentally disagrees with Biden’s approach, likening it to how centrist Democrats believed pulling the party more to the right was the key to overcoming Republicans.

When asked if he thought Biden had the right message, he wondered aloud how a message of restoring the Obama years might echo with a new generation of voters. “You have to look forward,” he said.

“Joe has two things going for him: The polls say he can beat Trump, and he’s worked with Barack and he’s saying that he wants to restore us to that day. Well, the challenge is that people are looking forward to a new day and aren’t necessarily looking to the old days,” Jackson told BuzzFeed News while attending Democratic National Committee events in Atlanta that also drew Biden and other 2020 candidates.

Now Biden is running for president a third time, and the 2020 race features several candidates of color, women, and an openly gay millennial, among others staking a claim to the future his opponents say he is not progressive enough to represent.

Biden’s 1988 campaign is now a footnote; Jackson’s would help shape the party. Biden unsuccessfully ran again in 2008 and ended up serving two terms as vice president under Barack Obama, the nation’s first black president. But Biden’s frustrations with Jackson lasted at least until that campaign 20 years later. His condescending comments about Obama early in his second presidential campaign — “the first mainstream African American [presidential candidate] who is articulate and bright and clean” — are usually remembered as broadly offensive. They also slight Jackson.

The remarks, which Biden acknowledged were about Jackson, caused a stir at the time. They brought an argument into sharp relief: Biden was casting himself then, as now, as a safe choice who could govern pragmatically. Jackson, a top lieutenant of Martin Luther King Jr., believed the future belonged to an emerging coalition made up of people of color and poor whites.

“But just as I and many other white leaders reject the voices of those who are calling for caution,” he continued, “you must reject the voices in this movement who tell black Americans to go it alone, who tell you that coalitions don’t work anymore, that whites and Catholics and Jews no longer care about the problems of black America, that only black should represent black.”

“We must reject the voices in my party who say — and you’ve heard it time and again — 'Much progress has been made, and now, now we must wait for the Reagan revolution to run its course,'” Biden told the mostly black audience that day in Baltimore, easing into his criticism of Jackson.

Biden’s decision to lash out to his left — now forgotten by pretty much everyone but Jackson himself — offers a glimpse of instincts and positioning that have changed little even as he has shifted his thinking at times to stay within the mainstream of his party.

The two men, both in their mid-forties, were preparing to run for president. And they were in the middle of a deep and enduring argument about Democratic politics. Biden wanted to build consensus. Jackson wanted to build a movement.

“My good friend — and he is my good friend,” Biden said of Jackson, adding a moment later: “We’ve never had any real differences.”

Said Jackson: “People like Joe don’t come in bunches like grapes. Give it up for Joe Biden.”

Jackson “doesn’t hold grudges,” Frank Watkins, a longtime Jackson aide who served as his press secretary during the 1988 campaign, told BuzzFeed News. “If he didn’t hold them against Bill Clinton ... you know what Clinton did to him was 20 times worse.”

Among other prominent clashes, Clinton embarrassed Jackson during a 1992 speech at a Rainbow Coalition conference. Clinton repudiated Sister Souljah, a black entertainer who had appeared at the conference after making provocative comments about the Los Angeles riots. ("If black people kill black people every day, why not have a week and kill white people?") Since then, “Sister Souljah moment” has become shorthand for politicians who go to showy lengths to distance themselves from a polarizing figure or group within their party.

There was no such thing as a Sister Souljah moment in 1986, but what Biden did at that year’s NAACP convention would have fit the definition. Biden did not mention Jackson by name, but he said afterward that the “reject the voices” admonition was directed at him.

"Jackson has done some really phenomenally good things,” Biden told reporters, according to the Washington Post. “But you can't go out and say this is class warfare. You can't try to pit the Rainbow Coalition, blacks, Hispanics, poor whites, gays, against the middle class."

During the speech, a black leader on the dais to Biden’s left nodded along as he delivered the crux of his critique. Biden then elaborated by noting how white voters helped make Douglas Wilder the first black candidate elected statewide in Virginia the year before. He then praised New Jersey voters in a majority-black congressional district for recently choosing the white incumbent, Peter Rodino, over a black primary challenger. Left unsaid: Jackson had campaigned for Rodino’s opponent.

“Americans — black Americans, white Americans — in each of these cases brought to life the promise of America by choosing excellence and competence over race,” Biden said. “These Americans are saying that their cause is our cause and ours is theirs. For this is the moral issue that goes to the core of our soul as a nation. And it’s quite frankly bigger than anyone’s political ambitions. It’s bigger than any personal agenda, and it’s bigger than any presidential campaign.”

The speech established Biden as a mainstream Democrat who would not capitulate to Jackson or the left but at times also burnished some liberal credentials. He railed against “right-wingers” and spoke approvingly of the recently scuttled nomination of Jeff Sessions to a federal judgeship. (The future attorney general in the Trump administration had faced accusations of racism, including disparaging comments about Biden’s host that day, the NAACP.)

Biden also presented himself as someone willing to speak frankly to the black community and alluded to his longtime opposition to busing as a means to desegregate schools.

“The bitter but honest truth is that for a decade, our cause has been stalling,” he said early in his remarks. “And we all know in our hearts that we’ve made some mistakes. For when our priorities were access, accommodation, education, and voting, we triumphed. All America stood with us. However, in the last decade we allowed the agenda to drift from these goals. Busing and quotas became the priorities, and our enemies on the right used the initiatives to regain the initiative. To the nation, they cast the civil rights debate in terms of black children being able to move ahead only if white children were forced to slide behind.”

Archived video from C-SPAN shows Biden received at least a partial standing ovation at the end of his 40-minute speech.

“Give our senator another great big hand,” Benjamin Hooks, executive director of the NAACP, said before repeating Biden’s last line: “Our time has come.”

After the speech, the influential newspaper columnists Rowland Evans and Robert Novak praised Biden for what they saw as his bravery in taking on Jackson. “To beard Jackson at the national NAACP convention in Baltimore would be a mark of courage, particularly when his speech defended his anti-busing stance,” they wrote of Biden. “Courageous it was.”

Jackson was not impressed when word got back to him. He told the Washington Post that Biden had “preached away from the storm” by waiting until he was away from the lectern and in front of the press to confirm he was ripping Jackson. Jackson traveled to Biden’s home state of Delaware a few weeks later for what United Press International reported as a similarly indirect rebuttal: Jackson had “described the Democratic Leadership Council, to which Biden belongs, as the Democratic Leisure Council — ‘yuppies’ who ‘part their hair to the left like Kennedy but vote to the right like Reagan.’”

Things were warmer between Biden and Jackson just a few years earlier. As Jackson was preparing for his 1984 presidential campaign, Biden addressed his organization, joined hands with him in a mock victory pose, according to the Associated Press, and told the crowd he was “seeking the vice presidential nomination on the Jesse Jackson ticket.”

But come 1987, about a year after the NAACP convention, Biden flatly rejected the idea of Jackson as his vice president.

“If you’re asking whether I’d choose a black man or woman for a running mate, the answer is yes I would,” Biden told a Boston television station. “If you’re asking whether I’d choose Jesse Jackson, the answer is no. I would not choose one to be my running mate who did not have experience in government, who hadn’t held elected public office. Jesse Jackson is going to make a significant contribution to this race, but he would not be my choice for vice president.”

Jackson later poked at Biden’s pride during a candidates forum on PBS, calling him “Vice President Biden.” But when Biden ended his campaign, Jackson was gracious, according to the Associated Press, saying he brought “a zest and a vitality” to the race.

Watkins, Jackson’s press aide at the time, only vaguely recalled the slights.

“I don’t recall any great tension between the two of them,” he said. “Some, maybe.”

Jackson last week had a sharper memory. Biden and the centrist Democratic Leadership Council, Jackson said, tried to win back Reagan voters. “Now he is trying to regain the glory of Barack’s election, and he’s trying to pick up Trump votes. The vote is ahead, not back. Our future is in front of us.”

Steve Phillips, a veteran of Jackson’s presidential campaigns in the 1980s, connects Biden’s strength as a 2020 frontrunner to the reputation he forged as a loyal partner to Obama as his running mate and as vice president.

“It’s comical, perverse or whatnot, that because you’ve got black people who think Biden runs well with white people, he has a lot of support among black people, and that’s what’s lifting him up in the polls,” said Phillips, the founder of Democracy in Color, a multimedia platform dedicated to race and politics, who is supporting Sen. Cory Booker of New Jersey in the presidential race.

“So it’s a very odd and ironic situation,” Phillips added, “but it will all be tested severely when we get to Iowa and it’s not clear Biden’s going to be able to withstand that test.”

In Atlanta last week, Jackson showed an interest in newer candidates such Booker, South Bend Mayor Pete Buttigieg, and Sens. Kamala Harris of California and Elizabeth Warren of Massachusetts. He acknowledged that Biden’s name recognition and eight years as Obama’s vice president are helpful but also noted that Biden’s record as senator is “drawing fire.”

During his remarks at the DNC fundraiser, Biden made several passing references to “Jesse,” including once as he issued a warning against Democrats committing acts of “fratricide,” lest the party assist Republicans in reelecting Trump: “I don’t think that most people foresaw — I think Jesse knew but I didn’t — that we would see a return of this viscousness, this sort of notion of pitting people against one another that we are seeing now.”

On another reference, Biden invoked Jackson in the middle of what he said was a strident defense of the possibilities of America as he spoke about feeling the weight of a black man picking him on the way to Washington to be sworn in as president and vice president.

Jackson was diagnosed with Parkinson’s disease in 2017, but in Atlanta, he told friends in private that he’s been feeling much better of late. It seemed at least for a time possible that Biden and Jackson would clash again — and soon.

After Buttigieg, the openly gay, 37-year-old mayor from Indiana, addressed the DNC audience in Atlanta, he walked toward the large media throng that had gathered to ask him questions outside of the room where he spoke. About halfway toward the front of the cameras, a thick hand in a brown jacket extended in front of Buttigieg, who appeared to be caught off guard before he stopped to look up and see who it was.

It was Jesse Jackson. ●

Katherine Miller contributed reporting to this story. Darren Sands reported from Atlanta.