Barack Obama has vowed to remain neutral during the Democratic primary, opting to counsel any candidate who approaches him, and eventually to throw his weight behind the Democratic nominee. But the former president does appear to have at least one strong personal investment in the primary: ensuring his ex-veep doesn’t tarnish his reputation on the campaign trail.

As the New York Times reported on Friday, Obama has taken an active interest behind the scenes in Joe Biden’s presidential campaign—not, it seems, to help his former vice president beat out the rest of the crowded field of 2020 hopefuls, but to shield him. Obama counseled Biden several times before he entered the race in spring, the Times reported, and the former president “cast his doubts” about the pending campaign. “You don’t have to do this, Joe,” Obama told Biden, a source familiar with their conversations told the paper. “You really don’t.”

After Biden entered the race anyway, telling him that he could “never forgive himself” if he didn’t personally try to oust Trump, Obama began pushing for Biden to “expand his aging inner circle,” according to the Times. His advisors needed to ensure Biden didn’t “embarrass himself” or “damage his legacy,” Obama told campaign staff in a March meeting, per the report.

Biden entered the race as the early frontrunner, riding high on his name recognition and revered “Uncle Joe” reputation within the establishment. While he continues to lead in most polls, he’s also drawn frustration and concern over his frequent gaffes. His blunders, along with renewed scrutiny of his decades-long record in Washington, have not only allowed competitors like Elizabeth Warren to cut into his lead in polls, but may also be turning off some in his own party, particularly in the progressive wing. His verbal flubs on the 2020 trail have reportedly even led some allies to suggest he curtail his campaign schedule. But just as he brushed off Obama’s concerns, it seems unlikely he’ll heed that advice. “Joe Biden has spoken his mind his entire life, which voters know and love about him,” Kate Bedingfield, Biden’s deputy campaign manager, told the Hill on Thursday. “He’s a real person, he’s authentic, and that will never change.

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