CARROLL, Iowa -- Jeb Bush made his final pitch to Iowa voters here ahead of the caucuses, adjusting his glasses as he looked across a room of around 100 voters packed into a small, lodge-type venue. The GOP presidential hopeful painted himself as the only candidate who can take on Democratic front-runner Hillary Clinton in the general election, a strategy most of his rivals use in trying to win over voters.

Throughout this unconventional election cycle, Republicans have depicted Clinton as unethical and power hungry, and a disaster of a president-in-waiting. But for some in the crowd, she is also seen as merely the second-worst person running for office -- the top honor going to their party's own front-runner. And if the results play out the way that the polls suggest, they could end up reluctantly supporting her come November.

“I think I would probably vote for the Democrat if [Donald] Trump becomes the Republican nominee,” said Jim White of Westside, Iowa, who has decided to support Bush. “The method that he tries to bully and operate in doesn’t work for me."

“In the long run, I don’t want anyone like Trump to be the head of our country,” White added. “I just don’t think his personal background, his way of handling things doesn’t allow him to be an effective leader -- that’s why I’d be willing to vote for the Democrat, to make sure he is defeated.”

Jonathan Ernst / Reuters

Donald Trump's strategy (if you can call it that) of bullying, harassing and, at times, humiliating his primary opponents has proven far more successful than anyone could have predicted. A Des Moines Register poll released on Saturday night showed him poised to win the Republican caucus on Monday. But it hasn't been cost-free.

Some of those who back the candidates on the receiving end of Trump's vitriol now say they would feel more comfortable voting for the Democratic nominee or an independent candidate, or simply not participating in the general election if the real estate billionaire becomes the Republican nominee.

“I could see myself deciding not to participate if it came down to that,” said Jaclyn Krause, a high school senior. “I am not a fan of Trump. He’s arrogant, he says whatever he wants to; he’s just an entertainer."

This dynamic is particularly true for backers of Bush, who has received, by far, the most incoming insults from Trump. Trump has continuously mocked the former Florida governor, calling him “low-energy,” a “loser,” an “embarrassment” and “dumb as a rock” for spending so much money on a rudderless campaign. And while Bush's support in Iowa has whittled down to single digits in the polls, those who make up the single digits aren't necessarily the forgiving type.

“I would absolutely not support Donald Trump if he becomes the nominee,” said Naomi Neu, 75, who caucused for Mitt Romney in 2012 and who recently decided she would caucus for Bush. “I would vote for the Democrat, or Michael Bloomberg if he decided to run as an independent. I think I’m trying to make a statement by caucusing for Jeb. It’s not going to be a very big statement. I think it just depends on how many people get out. Hopefully, we will be surprised.”

Bush supporters are not the only Iowa Republicans who pledge to hold grudges against the Donald. Several voters at a rally for Sen. Marco Rubio (Fla.) on Saturday said they couldn’t see themselves supporting Trump either.

Rebecca Anthony of Altoona, Iowa, and her husband, Douglas, have narrowed down their choices in anticipation of the caucus on Monday night, and they both say Trump is at the bottom of their list.

“If it came down as just Hillary or Donald, and there was no independent running in the general election, I would go with Hillary,” Rebecca Anthony explained. “He’s that scary; I would have no choice.”

Douglas Anthony said at this point in the election, he would be unsure of how he would vote in that situation. “It would be hard to choose between the lesser of those two evils,” he said, adding that he and his wife still have faith that the Republicans can nominate a different candidate.

David Becker / Reuters

HuffPost Pollster, which aggregates all publicly available poll results, shows Clinton with more than a 6-point lead in a matchup against Trump.

Trump, in some respects, has already acknowledged that he faces a deficit of trust among GOP voters should he emerge the party's nominee. He has openly talked of pivoting in the general election toward a more moderate posture. And it stands to reason that currently aggrieved Republicans would warm up to him as he becomes less abrasive. Some admit even now that they would reluctantly support Trump should he get the party's nod.

“I would hold my nose and vote for Trump,” said Ed Acoymo of Ankeny, Iowa, who has recently decided to back Rubio. “There are some things that scare me about him, but he would probably appoint better Supreme Court justices than one of the Democratic presidential candidates.”

But while Trump would have to do yeoman's work to win the support of those voters who currently back other Republican candidates, his supporters showed little reluctance to back another GOP nominee should Trump end up losing.

Matt, a voter from Dubuque, Iowa, who showed up at a Trump rally there on Saturday, says he is prepared to caucus for Trump on Monday, but if the former reality TV star weren’t to secure the GOP nomination, he’d consider supporting a different Republican candidate in the general election.

“Depending on who the Republican candidate is, maybe Rubio,” explained Matt, who did not want to disclose his last name. “If it’s between a Republican and Hillary, I’d do it.”

Shannon Lundgren says she’s currently supporting Trump, but is also interested in Ben Carson and Rand Paul, a senator from Kentucky.

“I just think we really need someone who’s going to go in there and tear things up just to reverse some of the damage that’s been done,” she said. “I’m obviously going to stand behind whatever Republican candidate we have.”

Igor Bobic contributed reporting from Dubuque, Iowa.

Note to our readers: Donald Trump is a serial liar, rampant xenophobe, racist, misogynist, birther and bully who has repeatedly pledged to ban all Muslims -- 1.6 billion members of an entire religion -- from entering the U.S.