According to a new story in Vanity Fair, former Vice President Joe Biden is feeling a bit glum as he reads reports of his former boss, Barack Obama, meeting with Beto O’Rourke, Sherrod Brown, and other Democrats who are thinking about launching a 2020 campaign for president. Biden has been long considered the de facto frontman in the 2020 race, though no one – including him – has officially announced their candidacy yet. But with an undoubtedly crowded primary field ahead (some reports have suggested as many as 40 Democrats may jump into the race), an endorsement from former President Obama would be a big help in separating the wheat from the chaff.

And Biden, naturally, thought he would be right in line for that endorsement.

From Vanity Fair:

Word of Barack Obama’s mid-November meeting with Beto O’Rourke cheered the millions of O’Rourke fans who want the Texas congressman to run for president in 2020. And it delighted the political pundit-verse, which is always hungry for new gossip and intrigue. Joe Biden, however, is said to have been less than thrilled. Obamaworld insiders describe the former vice president as upset—not specifically by Obama’s conversation with O’Rourke, but by the former president’s willingness to talk to other plausible Democratic contenders while Biden is still deciding whether to run himself. “This is unequivocally false. Period,” Biden spokesman Bill Russo says. So just how does Biden feel about his ex-boss chatting with potential primary rivals? “I’m not going to comment further,” Russo replies.

Obama has nothing against Biden—in fact, he still loves Amtrak Joe, according to a person familiar with the ex-president’s thinking. And Obama has been strict about not publicizing who has sounded him out. But he does not want to repeat what he considers a mistake from 2016, when the Democratic establishment wrapped its arms around Hillary Clinton as the party’s nominee early in the process. “He contrasts that with 2008, when he came out of the primaries and he’d been to all 50 states and he was fucking ready to take on John McCain,” one former Obama advisor says. “So his position this time is, ‘If you’re serious and you want to talk, I’ll talk to you.’ As things unfold, he might say, ‘Let’s all stay focused.’ But he’s not going to pick a winner.”

Obama is still plenty popular with the Democrat voter base, but his endorsement is not going to be a make-or-break moment for any of the top-tier candidates. It could even prove to be an anchor around some of the more progressive-style politicians, who would like to take the party further into socialist territory. Obama’s endorsements certainly didn’t do Andrew Gillum or Stacey Abrams any favors in the midterms. Nor did his stumping help Hillary Clinton overcome her intense negatives.

In this instance, however, it could be a death-blow to Biden’s presidential aspirations if Obama were to throw his backing behind another candidate. Being around when Obama was president is just about the only thing Biden has to run on. If he can’t even claim the support of his “bro,” he’s going to find it pretty difficult to swing those Obama-Trump voters back to the Democrats.