In 2019, Barack Obama and Donald Trump were America’s most-admired men.

Which is just one reason why Obama’s endorsement of Joe Biden this week was billed as a momentous political event. Obama is a divisive figure — could the first black president in a country like America have ever been anything but? — but he’s the last Democrat to cobble together a winning coalition. He motivated a massive turnout of black voters, played on his pop cultural cache to excite millennials and persuaded upper Midwestern whites to support him.

At its core, Biden’s candidacy is premised on restoring that halcyon Obama era — electorally as much as politically. That’s why Obama will be key to Biden’s success, perhaps more so than any other campaign surrogate in the modern era. The former vice president, while respected, was seen as a weak candidate until his blowout primary victory in South Carolina. Yet the support of those who helped him win that race — black Democrats — is premised largely on his having served under Obama. Biden has yet to crack the nut of gaining sufficient support from white Obama-Trump voters in key states, and his campaign is at an unprecedented stand-still, as at least 28,000 Americans have perished in a pandemic that threatens to overshadow the next months, if not years, of the nation’s life.

Obama, possessed of an almost preternatural equanimity, could be a comfort to Americans as an unsettling presidential campaign plays out. There’s one question that looms large, though: Are Obama’s political powers in 2020 the same as they once were?

The former president retains great political assets. His average approval rating in 2009, the first year of his presidency, which was dominated by the Great Recession, was 56.5 percent, and while it dipped into the 40s for much of his tenure, Obama’s post-presidential approval numbers have been strong. Gallup’s first retrospective job approval rating for Obama in 2018 — a barometer for how his presidential legacy was faring — was 63 percent. An average of YouGov polling collected between February 2019 and February 2020 found that 55 percent of Americans have a positive opinion of Obama. That’s higher than Biden’s approval in polling averages, which is about 45.7 percent, according to RealClearPolitics. Obama also outpaces Trump, who is currently at a 44.1 percent approval rate, according to the FiveThirtyEight tracker. A popular surrogate at his side during a time of crisis should be nothing but a boon to Biden.

Obama’s specific appeal to demographics that turned out in lower numbers during the 2016 election could be another way that he helps his former vice president. Democrats’ narrow loss in 2016 could have been due to any number of factors, but some have pointed to decreased black turnout in key states as a potential culprit. While Biden has done well with black voters already — his win in the South Carolina primary propelled him to the nomination — Obama’s presence will likely continue to help him. The same goes for young voters. While Biden, by dint of being a Democrat, is likely to do well with the youth vote, he struggled with the demographic during the primary. Obama’s presence on the campaign trail — even a virtual one — could be the youthful tonic that Biden needs, after the reputational hit he’s taken with left-leaning millennial and Gen Z voters.

Biden’s ultimate test, though, will be whether he can win back the largely white Obama-Trump voters in the general election, and it’s unclear whether even Obama himself can help him do that.

Obama’s presidency accelerated a political realignment that came to define the 2016 election: whites without a college education making an exodus out of the Democratic Party. States with large populations of these white voters, like Wisconsin, Ohio and Pennsylvania, which Obama counted as key to his winning coalitions, slipped away from Clinton. In 2008, roughly half of non-college-educated white people identified as Democrats, and half identified as Republican. By 2015, only a third were Democratic-leaning.

Gallup data shows that Obama’s approval ratings with whites nose-dived over the course of his presidency: In January 2009, 63 percent of whites approved of him, but only 47 percent did by January 2017, when he left office. Biden, who has long played up his “middle class Joe” persona, is not yet faring well with the kind of middle-class white voters his candidacy is premised on winning back. A recent analysis from Nate Cohn at the New York Times shows that Biden doesn’t have a wide lead in key states that swung the election in 2016 — his margin over Trump in states packed with Obama-Trump voters, like Wisconsin, Pennsylvania and Michigan, ranges from 1 to 4 points, according to the analysis.

That not even Biden has won over these voters could start to smart for some Democrats, especially since the party put forth its most diverse field of primary candidates only to nominate an older, white man. Finding relative political safety in a white nominee, however, was long in the making. In 2017, I wrote about a newly prominent group of young, white male politicians whose political resumes and communication styles reeked of Obama-imitation. They had all of the hallmarks of the former president — type-A discipline, good resumes and relatively moderate politics — but of course, they were all white. They were less likely, perhaps, to spook moderate white voters who had come to resent the party of the first black president.

In some ways, Biden is the ultimate “white Obama” candidate — a white, male Democrat trying to ride the former president’s “hope and change” coattails, but also put the traditional white American male face to the presidency. Much remains fluid about the 2020 election, including what form campaigning and voting will even take, so it’s hard to say if Obama’s resurging presence in the news during a time of crisis — which might very well extend into the high campaign season of the fall — could remind Obama-Trump voters what they liked about him (and Biden by extension) to begin with.

But that’s a big “if.” America, which has ridden an emotional political roller coaster for the past four years, seems to be only approaching the apex of another steep peak on the ride. The next seven months remain largely uncertain, but, queasily, seem to promise only one thing for sure: a terrifying ride. It’s anyone’s guess if Obama, a figure from our calmer past, will have the power to soothe and motivate key voters in our uncertain times.