Whatever its ultimate effect on the campaign, the first presidential debate of 2024 certainly did not cast the United States in a favorable light.

It featured two elderly men — one 81, one 78 — who insulted each other and who most Americans wished were not the two major-party candidates for president. One candidate told frequent lies and portrayed the country in apocalyptic terms. The other struggled at times to describe his own policies or complete his sentences.

The image of the nation as some combination of unhinged and doddering was especially striking at a time when the U.S. is supposed to be leading the fight against a rising alliance of autocracies that includes China, Russia and Iran. “I am worried about the image projected to the outside world,” Sergey Radchenko, a historian at the Johns Hopkins School of Advanced International Studies, wrote on social media. “It is not an image of leadership. It is an image of terminal decline.”

Radoslaw Sikorski, Poland’s foreign minister, seemingly compared President Biden’s performance to Marcus Aurelius’ failure to find a competent successor in ancient Rome, which hastened the empire’s decline. “It’s important to manage one’s ride into the sunset,” Sikorski tweeted.

Russian officials — whose recent online behavior suggests that they are rooting for Donald Trump — portrayed the debate as a sign of American weakness and disarray. The result “is good for us,” Dmitri Novikov, a Russian lawmaker, said on state television. “Destabilization inside an adversary is always a good thing.”

Where does the campaign go from here? That’s the subject of today’s newsletter.

Solid vs. shaky

Most Republicans are committed to Trump, even as he continues to tell lies and reject core principles of democracy. The situation with Democrats and Biden is obviously more uncertain.

The Biden campaign and its allies have tried to describe the night as just another bad debate performance (as my colleague Michael Shear explains), not so different from weak showings by Barack Obama, George W. Bush and Ronald Reagan. But it was different. Biden seemed incapable of accomplishing basic political tasks, such as explaining what he had done in his first term, what he wanted to do in a second term and how his opponent’s policies could harm the country.

Since the debate, Biden has looked more competent in public appearances. But his struggles during the debate will be hard to forget. Yes, he may sometimes be as sharp as ever. And, yes, he has accomplished a great deal during his first term. Nonetheless, he also sometimes appears to be a typical 81-year-old whose acuity is uneven and whose fitness for the presidency is questionable.

In a CBS News poll conducted after the debate, only 27 percent of registered voters said that they thought Biden had the mental and cognitive health to serve as president. By comparison, 50 percent of voters said Trump did.

1. Polls

Several major pollsters are likely to release post-debate polls in coming days, and they will shape political discussions this week.

Before the debate, Trump had a very small lead in national polls and a slightly larger lead in most swing states. If the polls remain similar after the debate, Biden’s aides will be able to argue that it didn’t alter the race’s dynamics. The aides probably won’t put it this way, but it would suggest that swing voters already understood Biden’s age was a problem before the debate.

If Biden lost meaningful ground, however, the political atmosphere could change quickly. More Democrats who now support Biden — or who at least haven’t called on him to drop him out — could begin to oppose him publicly.

(You can follow the polls this week through The Times’s polling averages.)

2. Donors

A key group to watch will be Democratic donors. Without the money that Biden’s campaign expected to raise in coming months, it may struggle to run enough advertisements to frame the election as it hoped — as a choice between a decent man who cares about Americans and a selfish man who cares only about himself.

During and just after the debate, many donors felt panic, and many still do. But Biden’s campaign has kept the criticism from spiraling over the past few days, as this Times story documented.

When polls come out this week, it will be worth watching the reaction of major Democratic donors, including those who speak to the media anonymously. They are likely to react more quickly, and more candidly, than senior Democratic politicians.

3. Democratic leaders

Ultimately, the response of Democratic politicians will probably be decisive. So far, top Democrats, including Barack Obama, Bill and Hillary Clinton, congressional leaders and governors, have publicly backed Biden. In private, some have been more alarmed.

Top House Democrats — including Hakeem Jeffries, the party leader, as well as Nancy Pelosi and James Clyburn — have questioned his viability in private, according to NBC News. If Democrats do mount a serious effort to persuade Biden to step aside, politicians who have worked with him for years are likely to be the messengers of doom.

The chances that Biden quits the race seem small this morning — significantly smaller than they did during the debate on Thursday night. But the situation is less settled than Biden’s aides have tried to suggest. And the next several days will matter much more than early July usually does in a presidential campaign.