Leslie Dellinger, a 41-year-old entrepreneur from York, South Carolina, wants to see Donald Trump defeat the Democratic presidential nominee this November — she’s just not convinced the nominee will be Joe Biden.

Instead, Dellinger — one of the few thousand people who showed up to a Donald Trump rally the day before the South Carolina primary — believes Democrats may swap Biden for Vice President Kamala Harris, who Dellinger says is “not even a little bit qualified” to be president.

“I wouldn’t be surprised if they tried to remove him and put in Kamala Harris and have her run,” she said.

Talk to almost any Republican at a grassroots event and you’ll hear some version of this theory: that Democrats will end up nominating someone besides Biden at their August national convention. Some believe there’s even a nominee-in-waiting to replace the 81-year-old president — who hasn’t suggested he intends to step aside, despite mounting concerns about his age and health. Their predictions for who this person might be range from the plausible — California Gov. Gavin Newsom, who many see as a likely candidate in 2028 — to the totally ridiculous, like former President Barack Obama.

This conspiracy, though, has some grounding in the real concerns that Democrats whisper about in private, and the grim warnings beginning to surface in polls of the election eight months away. A Bloomberg News/Morning Consult poll released Thursday found Trump beating Biden in seven key swing states that helped Biden defeat Trump in 2020. Respondents largely found Biden to be too old, while many considered Trump, the likely GOP nominee, to be dangerous.

Trump has helped to legitimize the notion that he won’t be facing Biden in November, even as polls show the former president gaining on Biden, which should be enough of a reason for Trump to hope the election is a repeat of 2020. “I personally don’t think he makes it,” Trump told Sean Hannity during a Fox News town hall back in December.

Since then, Biden’s possible replacement has become the subject of wild speculation on the right. Organizers of the Conservative Political Action Conference (CPAC) surveyed attendees at its annual confab last weekend about who they think will be the eventual Democratic nominee. A majority named former first lady Michelle Obama, who famously hates politicking in all its forms. Others cited Harris, Newsom and ex-Democrat Robert F. Kennedy Jr.

Michelle Obama’s name kept coming up in conversations at Trump’s rally in Rock Hill, South Carolina, last Friday. Trump supporters who spoke with HuffPost feared Democrats would tap Obama because she’d make a better candidate than Biden. (Despite her dislike of politics, Obama is one of America’s most popular political figures.)

“I believe if she does it, she’ll win because society is just more about looks and no substance. We just look at popularity more than anything else,” said Doug Smith, a postal worker from Rock Hill.

CPAC even dedicated a panel — with the deranged title “Cat Fight? Michelle vs. Kamala” — to dissecting the imaginary political rivalry between two of the party’s most prominent Black women. Radio host Monica Crowley warned Republicans to be ready for Obama to swoop in and clinch the nomination: “Michelle Obama is the worst-case scenario because she poses the most threatening challenge to Trump,” she said.

Biden’s campaign, in an email to HuffPost, called this theory “bizarre” and said it was “happy to confirm that’s not the case.”

Republicans, however, may be taking some of their cues from real election influencers who are slowly beginning to question the wisdom of another Biden run and suggesting a way that Democrats might coalesce behind someone else. This month, The New York Times’ Ezra Klein, one of the paper’s most prominent liberal columnists, argued it’s time for Biden’s inner circle to intervene and convince the president to allow delegates to get behind another nominee. Election analyst Nate Silver also wrote this month that Biden needs to campaign more aggressively or “stand down.”

This week’s Michigan primary revealed warning signs for both Biden and Trump. Biden lost 13% of the Democratic primary vote to “uncommitted” voters protesting his Middle East policy and another almost 6% to Minnesota Rep. Dean Phillips and author Marianne Williamson. Trump, meanwhile, lost 30% of the GOP primary vote to former U.N. ambassador Nikki Haley.

The Trump supporters who spoke with HuffPost recently regarded the potential for another Democratic nominee with a mix of glee and also fear over whom Democrats might find to run, though some of their predictions would not be remotely possible.

A South Carolina woman who would only identify herself as Debbie because she was afraid of online backlash from her remarks, believes that it’s really Barack Obama who’s eyeing a return to office for a third term, which is not allowed under the Constitution.

In his speeches “he talks about a third term. He talks about controlling. He talks about all those things,” she said. Even though it’s illegal, she said she wouldn’t put such a scheme past Democrats, who are “sneaky little bastards.”

She also touched on another theme that’s widespread on the right — that Biden isn’t even in charge at the White House. “Is he even running? I just think it’s all a sham. I think they’re trying to figure out what is going on and how people are going to react.”

Joe Schaub, a 67-year-old from Columbia, South Carolina, said it’s clear that Biden is simply too old now to do the job. “He was a schmuck senator,” Schaub said. “Now he’s old and dumb. That’s a bad combination. You just can’t replace old.”

“The problem is, who else do they have?” said Danna Hopkins, a 60-year-old financial controller.

Erin Adamek, a 55-year-old homemaker, said it won’t make a difference who Democrats wind up choosing because Trump would beat them all. “I don’t really care who runs,” because we’re still gonna win, she said.

CORRECTION: A previous version of this story cited a South Carolina city called Winthrop. Winthrop was actually the university where Trump spoke.