Harry Truman was a politician whose career was coming to an abrupt end. Three years earlier, the former Missouri senator had assumed the presidency after Franklin Roosevelt‘s death. Despite visionary leadership that created the postwar world in which we still live, Truman was plagued by low approval ratings and mocked unmercifully even by members of his own party, who joined in chants of “To err is Truman” and “We’re just mild about Harry.”

When the embattled incumbent went to bed on election night in the fall of 1948, national commentators were declaring that Republican New York Gov. Thomas Dewey would be the next president of the United States. And by the time Truman awoke the next morning, the Chicago Daily Tribune was blasting out the bold headline, “Dewey Defeats Truman.“

Except, of course, he didn’t.

In a matter of hours, the American people disproved pretty much everything commentators and pollsters had been predicting for months. The political world shifted suddenly on its axis, and no one saw it coming.

Seventy-two years would pass before another presidential candidate’s fortunes would shift as abruptly as Truman’s did in the 1948 presidential election. And that vertiginous change just happened over the past 72 hours.

Joe Biden’s Super Tuesday resurrection was even more surprising than Donald Trump’s upset 2016 victory over Hillary Clinton. That campaign’s final 10 days were so thrown into chaos by then-FBI Director James B. Comey’s letter telling Congress the Clinton email probe had been reopened that an air of uncertainty hung over election night.

But last week, there was no question that Biden’s presidential run was dead in the water. His campaign was out of money; his political organization a joke; his support among black voters was collapsing. The former vice president’s path to victory was cluttered by a talented group of moderate candidates trying to elbow him aside, and he once again was being mocked as a man running for president since 1987 who had never won a single primary contest. The echoes of past gaffes and the fear of future failures hung heavy over Biden’s campaign headquarters.

And then South Carolina and Super Tuesday happened. Suddenly, Biden was invincible, rolling up stunning victories in Texas, Massachusetts and Maine and routing all challengers in Virginia, Alabama and Minnesota.

Super Tuesday brought even better news for Democrats focused on removing Trump from the presidency, with turnout skyrocketing in states such as Virginia. By the end of Super Tuesday, the rising Biden vote count from a coalition of suburban moderates, pragmatic white liberals and black voters of all backgrounds seemed to build a political wall strong enough to block Trump’s reelection bid.

That assumes, of course, that Biden will continue to improve on the campaign trail. He has been plagued by uneven debate performances this year, and there’s that pattern of gaffes and misstatements stretching back decades. Add to those concerns the withering criticism his campaign has received from party insiders, most prominently Rep. James E. Clyburn, the South Carolina kingmaker whose endorsement may have single-handedly turned the tide in Biden’s favor.

But Biden’s brand may finally transcend the occasional missteps. He is a trusted and tested national political figure known for his empathy, decency and, above all, ability to come back from the hardest blows. In a week, he proved his declaration to the New York Times editorial board — “I ain’t dead. I’m not going to die” — to be nothing less than political prophecy. Tuesday night’s results will only reinforce voters’ belief that when he gets knocked down, Jean Biden’s son climbs back to his feet, brushes himself off and walks back into the fight.

Use the Post Opinions Simulator to pick a state and see what might happen in upcoming primaries and caucuses.

The question now facing Biden is whether someone so accustomed to running presidential campaigns as an underdog can thrive as a front-runner. After all, he’s already had and lost that role once this cycle. How Biden handles this latest challenge will determine whether he can win key upcoming primary contests in Mississippi, Michigan and Florida. If he does, then Trump will soon be forced to reckon with something that he clearly fears more than any special counsel investigation or impeachment proceeding — a reelection campaign against Joe Biden. Trump was so desperate to avoid that matchup that he got himself impeached. Now, the only person who can stop it from happening this fall is Biden himself. But if the past week proved anything, it is that like Truman so many years ago, history’s wind is finally at Joe Biden’s back.

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