At the presidential debate between Joe Biden and Donald Trump on Thursday night, the current president did little to allay concerns that he was no longer fit for the demands of his office at age 81. The former president, on the other hand, unleashed a torrent of lies and disinformation on abortion, January 6, immigration and the outcome of the last election.

More than four months before the 2024 presidential election, calls are growing among Democrats for Biden to step aside in favor of another candidate. On Friday, however, Biden reiterated that he wants to stay in the race.

“He delivered the kind of performance that Democrats feared, the kind of performance that worried them in the run-up to the State of the Union,” said Chris Galdieri, a political science professor at St. Anselm College. “They didn't get Joe from the State of the Union, they got Joe, the (81)-year-old who is fighting a cold and looks and sounds like it. I always hesitate to talk too much about these things in the context of theater criticism, but I think the danger for him is that the visuals reinforce the concerns voters have that we know they have.”

In a recent Gallup poll, 67 percent of Americans said Biden is too old to be president. By comparison, only 37 percent said the same about Trump, even though Trump is only three years younger.

Thursday evening was also marked by numerous untruths from Trump. He called Biden a “very bad Palestinian,” said that the current president is being paid by China and that Biden is allowing millions of illegal immigrants to receive welfare. He also said on the subject of abortion that the Democrats would “take the life of a child in the eighth month, in the ninth month, even after birth,” and denied any responsibility for the January 6 uprising.

On the other podium, Biden lost his thread, mixed up numbers and at times struggled to fill the two minutes of speaking time allotted to him.

“This will give plenty of ammunition to people who develop negative campaign ads in the future,” said Andy Smith, director of the University of New Hampshire Polling Center. “Biden looked very old and not up to the task, and Trump was more than happy to repeat untruths and exaggerations.”

The age issue has weighed on Biden's poll numbers for months, but on previous occasions, such as this year's State of the Union address, he managed to allay some of those concerns with energetic and forceful speeches. That was largely not the case on Thursday.

But while talk of replacing him at the top of the ticket has continued to gain momentum, Galdieri warned that this is not necessarily a realistic option that would improve the Democrats' chances of winning.

“This has little to do with reality. I think the key thing here is that it's not a matter of, 'The president should resign and Vice President Harris should be the nominee.' Because if the president resigned, that's what would happen,” he said. “I can't imagine him dropping out of the race and not saying, 'By the way, all the delegates to the Democratic Convention who were elected to support me, I think you should support Vice President Harris.' And I just find it amazing that there are people who think, 'Oh yeah, we could just skip the first black woman to be vice president, who could be the first black president, the first female president.'”

In addition, the replacement candidate, whoever he would be, would not have gone through the rigors of a primary campaign that could expose his weaknesses or demonstrate his strengths.

“It would really be playing with fire for the Democrats to put up somebody who has never been in a primary, who hasn't had to go out and advocate to black voters in South Carolina, to urban voters in New York and Michigan and Atlanta and the like, and just skips all of those Democratic districts and gets the nomination because they say, 'Oh wow, they gave a really good speech,' or something like that,” Galdieri added. “I just think that sets up a really, really difficult campaign for somebody.”

The implications of Thursday remain unclear because it was the earliest presidential debate of a cycle. With Trump having to choose a vice presidential candidate, both parties' conventions coming up, future debates taking place and other unexpected developments looming, voters' decisions will be influenced by far more than a 90-minute debate.

“I don't think we should draw any final conclusions in the first few days after this,” Smith said. “We'll see how things play out, but it's June. Voters aren't really paying attention to the race yet. They won't really tune in until after Labor Day, so both Trump and Biden still have time to recover from this, but assuming there is another debate, I hope it's better than the last one.”