“You don’t have to do this, Joe, you really don’t,” former President Barack Obama reportedly told Democratic presidential candidate Joe Biden when the two discussed the 2020 race. Apparently skeptical of Biden’s decision to run, Obama — who remains exceptionally popular among Democrats — has made it known that he will not make a formal endorsement in the primary.

Biden has fully embraced the Obama legacy. The former president features prominently in a number of Biden’s campaign advertisements. Biden’s latest ad contains an implicit endorsement, according to Politico. As longtime Obama adviser David Axelrod put it, the ad “is a clever way of signifying Obama’s feelings about Biden, implying an endorsement the president has not made.”

The 30-second ad is a montage of black-and-white photos of Biden, and it features Obama’s speech presenting Biden the Presidential Medal of Freedom.

“We all know that on its own, his work does not capture the full measure of Joe Biden,” Obama says in the ad, describing Biden as a “a resilient and loyal and humble servant.”

Released ahead of Martin Luther King Jr. Day, the advertisement is the Biden campaign’s latest effort to maintain the former vice president’s strong standing among black voters in the south and across the country. According to a Biden adviser, Obama was made aware of the video.

According to some of those close to Obama, the former president is not exactly enthusiastic about Biden’s White House run. Others familiar with Obama’s thinking have suggested that the former president approves of Biden’s campaign as a means of preserving and continuing his legacy.

However, one Democrat, who is neutral in the 2020 race, shared details about a candid conversation with Obama. Apparently concerned about his former vice president’s “gaffe-prone nature,” Obama allegedly told the unnamed Democrat the following.

“Don’t underestimate Joe’s ability to f*ck things up.”

An Obama spokesman neither confirmed nor denied the allegation, stating that the former president’s team does not discuss such matters with the press.

Winning Iowa is imperative for Biden, who ran for president two times, dropping out after failing to generate momentum in the key caucus state. This time, although the Democratic primary seems to be a four-way race, Biden appears to have a real shot at winning the nomination.

As Axelrod suggested, the Biden campaign’s latest ad could help the former vice president impress Iowans.

“Barack Obama is a highly esteemed figure in the Democratic Party and perhaps nowhere more than Iowa, which really embraced him and launched him to the presidency,” he said.