“He believes that in order for Democrats to have confidence in the process that voters will have needed to have their say and as that unfolds,” said the person familiar with the president’s thinking. “He doesn’t really think it would serve the party well to interfere.”

But then you also have Congresswoman Alexandria Ocasio-Cortez, who campaigned for Sanders back in 2016 and has proven to be an electrifying surrogate for the senator on the campaign trail this cycle. On Thursday night, the freshman firebrand told Seth Meyers that if Biden wins the nomination, she will back him. “I’ve said throughout this entire process that what is so important is that we ultimately unite behind who that Democratic nominee is,” she said. “And I think it’s a two-way street. I’ve been concerned by some folks that say if Bernie’s the nominee, they won’t support him—and the other way around.” And Sanders, too, has said he would concede if Biden went into the convention with a plurality of delegates. ”If Biden walks into the convention, or at the end of the process, [and] has more votes than me, he’s the winner,” Sanders said in an interview with MSNBC’s Rachel Maddow on Wednesday.

Once there’s a presumptive nominee, Obama is likely to balance the needs of soothing the feelings of the losing side with the need to unify quickly to take on Donald Trump. “If there is a clear verdict on the part of voters, I don’t think he is necessarily going to wait until the convention to speak to it—but he may,” Axelrod said. “But I think his main point is that he thinks voters should choose the nominee, not him or some force from on high. And you know, I would remind everybody that a week ago there were people saying he ought to weigh in for Biden…. And you know what, Joe Biden is a stronger candidate today because he did it on his own. So the wisdom of Obama, at least from that point, is pretty clear.”

This inflection point could come fast with a flurry of primary contests just around the corner. On Tuesday, Democrats will cast their votes in Idaho, Michigan, Mississippi, Missouri, North Dakota, and Washington. Then, a week later, Arizona, Florida, Illinois, and Ohio will cast primary ballots. Of this batch of post–Super Tuesday states, Sanders won Michigan, Idaho, North Dakota, and Washington in 2016 (though a number of the contests were close). But looking ahead, Florida is the biggest prize, with 219 delegates up for grabs later this month. And polling released on Thursday showed Biden with a substantial 49 percentage point lead over Sanders in the Sunshine State.

Of course, extrapolating predictions based on 2016 primary results amounts to little more than reading tea leaves. And had polling been any indication headed into Super Tuesday, Biden shouldn’t have walked away in the lead. “The caveat is a caveat that I keep reminding myself of and everybody else, which is if there is nothing else that the last decade of politics should have taught us, it is humility. Things can change and one thing you can feel fairly confident of is that Bernie Sanders is no sooner going to walk out with a white flag than Joe Biden was a week ago,” Axelrod warned. “All that said, the onus has shifted and it is Biden who is in the lead car and Sanders chasing him.”

Obama did speak with Biden after the latter’s victory in South Carolina. He also has made a habit of calling each candidate who leaves the race after they bow out, according to the source familiar with Obama’s thinking. What Warren does also remains a crucial, potentially race-changing question. After dropping out of the Democratic primary on Thursday, the Massachusetts senator declined to immediately offer up her endorsement to either candidate. “If Biden gets it, it would signify a further consolidation and unification of the party because she obviously comes from a different wing of the party and she would be an extraordinary surrogate for him, especially given the attacks that are likely to come from the left, from Sanders. That would be very disruptive to Bernie Sanders and helpful to Biden if she endorsed him,” Axelrod said. “I think for Sanders, he needs something to reignite his engine here and having Warren come over and certify him and perhaps be a surrogate for him and deliver some blows to Biden would be a really valuable thing.” Who the two candidates might pick as their running mate also shouldn’t be underestimated, either.