Former President Barack Obama warned during the Democrat primary that his former Vice President Joe Biden could “f*ck things up,” an anonymous Democrat said according to a report in Politico.

The line was originally attributed to an anonymous Democrat source cited by Politico‘s Marc Caputo from a conversation the Democrat claims to have had with the former president about the 2020 primary. It suggests that Biden was not Obama’s first choice for the Democrat party’s presidential candidate in 2020.

“One Democrat who is neutral in the 2020 race and spoke to Obama about Biden’s gaffe-prone nature recalled the former president saying: ‘Don’t underestimate Joe’s ability to fuck things up,'” Caputo wrote.

That quote was first reported in January, but was revisited in a Politico story last week by Alex Thompson recalling how Obama supported his formal rival for the presidency Hillary Clinton in 2016 instead of his own vice president.

As both Obama and Clinton speak Wednesday night at the Democratic National Convention, with Biden set to formally assume the party’s presidential nomination on Thursday night, these rifts between the top Democrats seem particularly relevant.

Thompson’s piece noted that Obama himself formally declined to be interviewed for the story that includes the quote about Obama warning about Biden’s capabilities as a candidate.

Instead, Obama’s spokesperson provided a generic statement that said, “President Obama has been unequivocal in his respect for Joe’s wisdom, experience, empathy, and integrity.”

But Thompson did speak to several top former Obama White House officials, such as former Chief of Staff Denis McDonough and former senior adviser Valerie Jarrett, among others. Jarrett, in particular, has been working to smooth over any hard feelings from the past and back Biden, after the former vice president won the nomination.

Thompson also reported that Biden’s allies are still displeased with how Obama and his top aides anointed Hillary Clinton as his successor in 2016.

Even Biden was a little hurt by the actions of Obama’s team.

“I knew a number of the president’s former staffers, and even a few current ones, were putting a finger on the scale for Clinton,” Biden wrote in his political memoir after leaving office.

While Biden was still pondering a run for president in 2016, Clinton was figuring out how to stop him, Thompson reported.

Clinton campaign manager John Podesta estimated that Biden would run for president and even drafted opposition research on him, while negative stories about his career made its way into the media.

Biden himself wrote in his memoir that Obama “was not encouraging” about him possibly running against Clinton in 2016.

As Biden began exploring a campaign against Trump in 2020, the New York Times also reported that Obama “cast his doubts” about it in a conversation with Biden.

“You don’t have to do this, Joe,” Obama told Biden, according to a source familiar with their conversations, cited by the Times. “You really don’t.”

The August 2019 story, by Times reporter Glenn Thrush, also detailed that Obama believed Biden should not run in 2020, but became more active in his former vice president’s campaign.

In March 2019, Obama requested a briefing on the state of the campaign from top Biden aides

“Win or lose,” Thrush reported about Obama’s message to the team, “They needed to make sure Mr. Biden did not ’embarrass himself’ or ‘damage his legacy’ during the campaign.”