New York (CNN) Lisa Bowers, a Republican voter in New Hampshire, grew hesitant when asked the question: If the race comes down to Donald Trump and Hillary Clinton, who would you vote for?

"Honestly," she paused, "I'd vote for Hillary Clinton. At least with her, you kind of know what you're dealing with. He's just a loose cannon."

That was in December, when Bowers, 41, was sitting in the audience waiting for Jeb Bush to hold a town hall.

Months have passed.

Reached Tuesday night, just as Trump was barreling towards the nomination following a decisive win in Indiana, Bowers said she's done a lot more research on the two candidates.

"At this point, I would absolutely still vote for Hillary Clinton over Trump," she said. "It would be that, or not vote at all -- and I've never not voted."

Bowers is one of many in the GOP facing an uncomfortable decision. A new CNN/ORC poll shows that one-third of Republicans would be dissatisfied or upset if Trump becomes the nominee -- an all-but-certain fate now that Ted Cruz has dropped out of the race.

It's unclear just what those disaffected Republican voters will do. Some say they'll begrudgingly support the likely nominee. Others will simply stay at home or write in a candidate. Some, like Bowers, say they'll cast a vote for what they consider the lesser of two evils.

"I not a big Hillary Clinton fan," Bowers said. "But she has a balance, and Trump doesn't."

One party's division is another party's opening

Clinton has already started making her appeal to Republicans who can't stomach the idea of voting for Trump -- or "thoughtful Republicans" as she calls them. She's aiming to paint the billionaire as a divisive figure while branding herself as the candidate who can bring more people together, even across party lines.

Last week in Philadelphia, the Democratic front-runner called for the country to unite against candidates who "pit Americans against each other."

"If you are a Democrat, an independent or a thoughtful Republican, you know their approach is not going to build an America where we increase opportunity or decrease inequality," she said.

Clinton campaign press secretary Brian Fallon called these voters "reasonable" Republicans on Monday. Talking to reporters on a press bus, Fallon said a "broad call for coming together" is a message that could appeal to Republicans who are turned off by the "polarizing" effect of their party's standard-bearer.

More specifically, the campaign plans to focus on the same issues that it's been pushing the past six months -- like infrastructure investments, pay equity, a minimum wage increase and gun control. Such issues have seen support from at least some right-leaning voters.

Clinton aides and confidants also expect a Republicans-for-Hillary effort, where GOP businessmen and high-profile donors could back the former secretary of state over Trump.

One high-profile Republican has already said he'll support Clinton.

Mark Salter, a former longtime aide to Arizona Sen. and 2008 GOP presidential nominee John McCain, has been aggressively advocating against Trump. He's taken to Twitter and his monthly column for Real Clear Politics to assail the candidate.

In an interview on Tuesday, he described Clinton as the "least reckless" option between the two.

"She hasn't said she'd ban all Muslims; he did. She hasn't said she'd like to see other countries acquire nuclear weapons; he did," Salter said. "She is a more conservative choice, that's indisputable."

Asked if there's anything Trump can do to woo back those Republicans, Salter said he would need "a personality transplant."

"He's incapable," Salter said. "He'd have to stop being Donald Trump."

At the same time, Trump has peeled off a sizable amount of Democratic voters and unearthed voters who've never cast a ballot before. They're drawn to his outsider status, his forceful talk on trade and his rebellious tone against special interests and lobbyists.

With that said, Bakari Sellers, a former Democratic member of the South Carolina House and CNN political commentator, thinks Clinton will have the best luck with white Republican women and Republicans who are wary of Trump's not-so-traditional foreign policy views.

"For these Republicans, it's not so much a Democrat vs. Republican decision, as much as it is question of whether they want a leader of the free world that has no there there," Sellers said. "There's an entire wing of the Republican Party who understands what it means to protect our interests around the world and not pull back into this pre-WWII isolationism."

#NeverTrump or #NeverClinton?

But many Republicans have been less clear about how they'll vote in November, despite being hesitant about backing Trump.

Republicans coordinated this spring to launch a late attempt to stop Trump from clinching the nomination -- a movement dubbed #NeverTrump -- with groups spending money in states to stall the candidate's accumulation of delegates.

But as evidenced Tuesday night, the effort failed.

Boosted by Trump's dominating victory in Indiana, campaign manager Corey Lewandowski brushed off the #NeverTrump movement and called for party unity.

"I think all that's a passing fad," he told reporters at Trump Tower, before Cruz announced he was dropping out. "I think right now most of the people understand that Donald Trump is going to be nominee, whether they like it or not."

"It's time to bring everyone together and make sure that there's one focus, and that focus is ensuring a Republican controls the White House," he added.

Trump's allies believe many Republicans will warm to Trump eventually -- mostly out of a shared and overriding dislike for Clinton, who, like Trump, has negative favorability ratings.

Jesse Benton, co-chairman of Great America PAC, a pro-Trump group, said Trump may not be able to rally the Republican establishment leaders behind him but he's confident that Trump can get traditional Republican voters on his side.

"Give it a couple months of Trump being the presidential nominee without serious opposition and allow Republicans to focus their fire on Clinton," Benton said. "And I bet those numbers will change."

Some signs of unity could already be seen on Tuesday night. Republican National Committee Chairman Reince Priebus tweeted a show of support for Trump after Cruz dropped out.

"@realDonaldTrump will be presumtive @GOP nominee, we all need to unite and focus on defeating @HillaryClinton #NeverClinton."

.@realDonaldTrump will be presumptive @GOP nominee, we all need to unite and focus on defeating @HillaryClinton #NeverClinton — Reince Priebus (@Reince) May 4, 2016

Earlier Tuesday, Louisiana Gov. Bobby Jindal, whose own presidential campaign foundered last year after trying to take down Trump, said he'll support Trump as the nominee even if he's "not happy about it."

"I would vote for him over Hillary Clinton," he said.

#NeverEither

It happens every cycle. Voters and high-profile figures in politics pledge not to back the nominee but eventually many of them rally around the candidate.

But Tim Miller, an adviser to the anti-Trump group Our Principles PAC, whose resume also includes leading an anti-Clinton group two years ago, said both candidates this time are positioned to repel a chunk of the electorate.

"I suspect there will be some rallying behind Trump but I suspect he will bring about a uniquely new, opposite reaction, where people will be disgusted with him in the next six months of what I expect to be an erratic general election," Miller said.

At the same time, Miller cast doubt on the notion that Clinton can attract enough Republican voters to make a difference in the race, saying her effort to be seen as a unifier won't "pass the smell test for Republicans."

As for Miller himself, he's planning on writing someone else in.

"I would never vote for Hillary, ever," Miller said. "I can take neither and not win but still maintain dignity, which I think is important."