Biden tries to calm nervous Democrats. It won’t happen instantly.

No one is suggesting anything close to a rerun of those events this summer. But that extraordinary stretch of 1968 is a reminder that this week’s talk of replacing President Biden as the Democratic nominee comes with no easy solution and many potential unintended consequences.

Fears about the authoritarian potential of a second Trump presidency alarm Democrats, many independents and even some Republicans. The goal of defeating former president Donald Trump unites Democrats. Yet after Biden’s struggles in Thursday’s debate, the best way to prevent Trump from becoming president again divides them.

The distress among Democrats is understandable. Biden failed to do what he set out to do on Thursday. Instead of allaying concerns about his principal weakness — his age and his mental and physical acuity — he raised fresh doubts about his capacity to serve another term. The only issue for Democrats is what to do next.

The president’s team has moved swiftly to tamp down talk of swapping him out for a different nominee. It put out the word early Friday that he would not step out of the race voluntarily. Flash polls showed Trump to be the overwhelming winner of the debate, but Biden allies claimed that some focus groups offered a more nuanced conclusion. Yes, participants thought Biden had some terrible moments, but Trump, too, left some of those watching frustrated. Members of the team are quietly monitoring key party leaders for signs of unrest.

Biden’s personal contribution to the efforts to calm his nervous party began with a fiery speech at a rally on Friday in North Carolina. The contrast between the animated Biden who stood before a crowd of enthusiastic supporters in Raleigh and the halting and sometimes confused president who appeared on the debate stage in Atlanta could not have been starker.

“I know I’m not a young man,” he said to cheers of “Joe! Joe! Joe!” “Folks, I don’t walk as easily as I used to. I don’t speak as smoothly as I used to. I don’t debate as well as I used to. But I know what I do know. I know how to tell the truth. I know right from wrong. And I know how to do this job. I know how to get things done. And I know like millions of Americans know: When you get knocked down, you get back up.”

Those were scripted words. They were delivered with the vigor that the unscripted Biden so clearly lacked in the debate hosted by CNN. But if one debate does not define a candidate, as Biden’s supporters were saying in the wake of Thursday’s encounter, one rally cannot erase the impact of a debate performance that spotlighted Biden’s greatest vulnerability.

Tens of millions tuned in to at least some of the prime time debate, and only a tiny fraction watched the daytime rally. The rally was one way for Biden’s team to buy time as it tries to rebalance the campaign and work behind the scenes to prevent talk of the need for a new nominee or an entirely new Democratic ticket from turning into concrete action.

Hours after Biden was in North Carolina, Trump campaigned in Virginia. His rally speech was an extended attack on Biden, an echo of the debate. If the Democrats hope to put North Carolina, a state they haven’t won since 2008, in play, Trump and Republicans say they can put Virginia, which has shifted toward the Democrats since 2008, in play. In a few weeks, it may be clearer whether the electoral map is expanding, and in which direction.

Trump and his team were energized by what took place in Atlanta. He was not the Trump of the first debate in 2020. He did not interrupt Biden constantly, as he did four years ago, thanks perhaps to rules that muted the microphones of the candidate not having the floor. He had talking points his team had prepared and he delivered them with enough consistency to make his points.

Still, Trump lied his way through the debate, giving fact-checkers a cornucopia of things to correct, a highlight reel like no other. Biden tried to correct some of Trump’s misstatements but was neither crisp nor specific enough. A second debate is scheduled for Sept. 10, hosted by ABC, but no one is certain Biden will get a second chance to show that Thursday was an aberration.

Biden was asked by reporters about his debate performance on Friday morning. “It’s hard to debate a liar,” he said. That begs the question of why he was not better prepared. Everyone could have predicted that Trump would spend the evening saying things that were not true. If the president and his team had a strategy to counteract Trump’s falsehoods, the execution was clearly lacking.

For Biden, moving his party off the ledge and back to his side will require more steps. Friday’s work — the rally, the insistence that he will not step aside, the talk of money raised from grass-roots donors — was important but not sufficient. Notably, however, there were no defections among party leaders, despite the chorus of calls for a new nominee from some prominent party strategists and pundits.

So far, the Democratic establishment is holding steady, but House and Senate leaders must first be loyal to their own members’ interests. House Democrats have hopes of taking back control from the Republicans. Senate Democrats are in a high-stakes battle to hold onto their slim majority with a map that favors Republicans.

In the coming weeks, nervous Democrats will be assessing Biden’s performance as a candidate while keeping an eye on the polls. Any more slips by the president could be devastating. Just as worrisome could be a notable shift in the numbers toward Trump, who already has a narrow advantage in the battleground states. If Biden were to fall further behind, the alarms that were triggered on Thursday could increase in volume. The campaign also must worry about fundraising. Before the debate, there were signs of slippage, though the campaign raised good money the day of and after the debate.

Beyond reassuring party insiders, Biden must reassure concerned voters. It could take much more than a few rallies or more attacks on Trump as a threat to democracy to bring to Biden’s side the voters he will need to prevent Trump from winning an electoral college majority and being returned to the Oval Office.

Technically, delegates to the August convention in Chicago could replace Biden. They have the power. But such a move against Biden would be extraordinary, and those who are talking about replacing him don’t have a strategy or a candidate.

Biden could step aside voluntarily, but then what? Would he say he wants Vice President Harris to be the presidential nominee or say the process should be opened up to others? Harris’s public approval ratings are as weak as Biden’s, but she represents the most important constituency in the Democratic Party, Black women, and everyone knows that Black voters saved Biden’s candidacy during the 2020 primaries.

Harris will have more visibility than ever, not just because she has to be Biden’s most loyal advocate but because of her potential impact on the electorate. The fact that she was sent out for interviews on the cable networks immediately after the debate signaled the campaign’s belief that her voice and presence are needed to help bolster the president and show solidarity.

Democrats have other capable younger leaders who could be in the mix if they decide a different candidate than Harris is needed to win in November. They include California Gov. Gavin Newsom, Michigan Gov. Gretchen Whitmer, Maryland Gov. Wes Moore, Kentucky Gov. Andy Beshear, Georgia Sen. Raphael G. Warnock, Pennsylvania Gov. Josh Shapiro, Transportation Secretary Pete Buttigieg, Illinois Gov. J.B. Pritzker, Commerce Secretary Gina Raimondo and Colorado Gov. Jared Polis — among others.

Party activists see them as credible and attractive, likely aspirants for the nomination in 2028. Would they be ready to mount a presidential campaign right now? That’s a different issue. They are little known nationally and thoroughly untested in the presidential arena. They have not been vetted as national leaders always are. Their teams, too, are untested in presidential politics.

A fresh ticket might excite an electorate that is dissatisfied with the choice of Trump versus Biden. But any Democratic newcomers would carry sizable risks. After Thursday’s debate, however, few Democrats are discounting the risks of continuing with Biden as their nominee. That is the party’s dilemma four months out from the election.