Getty / The Atlantic

When Joe Biden entered this presidential race, he was flayed as an ally of segregation. Kamala Harris chided him for his defense of busing. His opponents roundly portrayed him as an architect of mass incarceration and an apologist for Strom Thurmond—as a clubbable senator not particularly bothered about the moral character of the backs he slapped.

These attacks were leveled not to suggest that Biden was a racial revanchist, but to reinforce a widely shared criticism of the man: He is not a visionary, but a malleable politician, with a barometrically attuned sense of the good.

But in Philadelphia yesterday, Biden delivered perhaps the most thorough-going and hard-hitting critique of American racial inequities ever uttered by a major presidential nominee. Certainly, no nominee has ever proposed such a robust agenda for curbing the abusiveness of police, and with such little rhetorical hedging.

In the face of upheaval, he’s given reason to hope that the traits that were his supposed weaknesses could prove to be his great strengths. If one of the ultimate purposes of protest is to push politicians, he’s shown himself a politician willing to be pushed. His tendency to channel the zeitgeist has supplied him with the potential to meet a very difficult moment.

One of the alleged truisms about older people is that they are cemented into ideological place. Their minds are said to have limited ability to switch political lanes. But in the past few months, Biden has altered his worldview. At the beginning of his candidacy, he announced himself as the tribune of normalcy. Donald Trump was a pathogen that had attacked the American host—and Biden would provide the cleansing presence that would permit a reversion to a pre-Charlottesville status quo.

What was so striking about his speech in Philadelphia was that it acknowledged that he had gotten it wrong. The country couldn’t return to a prelapsarian state of tolerance, because one didn’t exist. “I wish I could say that hate began with Donald Trump and will end with him. It didn’t and it won’t. American history isn’t a fairy tale with a guaranteed happy ending.” Faith in progress is the nostrum of liberal politics, yet Biden broke with that faith in Philadelphia, and by so doing, he seemed to concede his own failure to appreciate the depths of American racism.

Since the beginning of quarantine, Biden has been chided for disappearing from view—and he receives strangely little media attention when he does rear his head. Over the past few days, for example, he’s treated the protests with deference, something cable news has largely ignored. When he met with activists who berated the Obama administration’s record on race, he didn’t react defensively. Instead, he studiously took notes. The relatively few images that circulate show him engaged in the empathetic poses that so often seem overwrought, but that also project openness and respect. In a church in Wilmington, Delaware, he dropped to his knee, a position obviously reminiscent of Colin Kaepernick but also a stance of self-abasement in the face of awe-inspiring anger.

So much American history has transpired since early February, it’s easy to forget that Biden’s candidacy was salvaged in the South Carolina primary. In the aftermath of that victory, he spoke about the debt he owed to black voters. There’s a chance that this was, to borrow a phrase, malarkey. But in the former vice president’s antiquated style, where one’s word is supposed to be stronger than oak, this debt has already guided him to stake his candidacy on a clear statement of solidarity with the protests.

More than other figures in the Democratic Party, Biden can speak warmly about the protesters without risking political backlash. With his gaffes, which sometimes veer toward the politically incorrect, he’s hardly an easily caricatured avatar of wokeness. His penchant for cringeworthy remarks, and his old-time mannerisms, help cushion whatever anxiety some white voters might have about his tough criticisms of police and blunt condemnations of systemic racism.

On Monday, George Floyd’s brother spontaneously addressed a crowd at the site of his brother’s killing, clutching a bullhorn. Through his mourning, he tried to guide the shape of the protest movement that had risen in his brother’s name. He pleaded, “Educate yourself and know who you vote for. That’s how you’re going to get it. It’s a lot of us. Do this peacefully.”

It was as if he were distilling a body of political-science research that has shown why so many protest movements around the globe have fizzled out these past decades. Social media permit the quick gathering of crowds, but without the organizational infrastructure or robust agenda that can sustain a true movement. Terrence Floyd was urging something different: He wanted the crowds in the streets to think politically.

The challenge for the Biden candidacy is to bridge an alliance with a resurgent left. Biden, a creature of the Senate, has to convince young people rushing to the barricades that he’s worth a trip to the polls. And the challenge for the left is to accept that Biden is its greatest chance of achieving its long-held dreams. What he’s demonstrated over the past week is a willingness to play the role of tribune, to let the moment carry him to a new place.

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.