If Jeb Bush’s most loyal supporters were told last year the former Florida governor would be out of the 2016 U.S. presidential race by February, they most likely would have laughed out loud. Now, the prospect of not only seeing the Republican nomination go to billionaire businessman Donald Trump but also losing the candidate they believed would help the GOP retake the White House has set many of them back on their heels.

Within hours of Bush dropping out of the presidential race Saturday night, many outlets reported that some of his big donors were switching their support to U.S. Sen. Marco Rubio of Florida. As the presidential-nomination season heads toward Super Tuesday (March 1) with Trump looking stronger than ever, the establishment wing of the Republican Party is facing an increasingly fraught choice: either resign themselves to the New York real estate mogul or line up behind an alternative.

Although Rubio may appear to be a natural fit for big campaign contributors hoping to stop Trump in his tracks, Bush backers and GOP strategists say a sense of loyalty and the rivalry between the two Sunshine State politicians could make supporters think twice when choosing another 2016 presidential campaign to help finance.

“I think it’s important to take a little bit of time, take a breath and not do anything emotional,” said Fred Zeidman, a longtime Bush family friend and major Republican donor who backed the latest Bush to seek the presidency. Zeidman said a priority was choosing somebody who could win the White House in November. “It’s important to really assess who our best chance of really accomplishing that is and lending time and financial support to that candidate,” he added.

Like many Bush supporters, Zeidman said he was “disappointed” his candidate quit the race. However, Bush both ran his campaign and made his decision to drop out “for America,” he said. “What he did, the timing and his speech was about as dignified as I could have ever asked for and imagined,” Zeidman said. “Having been with the Bushes for so many years, it’s what you would expect from a Bush.”

Many Republicans have criticized those running Bush’s campaign and the pro-Bush super PAC Right to Rise for employing what they have called an outdated playbook and for going after Rubio and the other establishment candidates while largely ignoring Trump

“When you’re blanketing states with ads the way Right to Rise did, advertising works, and negative ads work even better,” said David Merritt, the managing director at Luntz Global Partners who was a fundraiser and presidential-campaign adviser for former U.S. Speaker of the House Newt Gingrich. “If Donald Trump wasn’t in the race, advertising would have worked the way it always does.”

This election cycle, the millions of dollars spent on attack ads was no match for Trump’s earned media. Despite the animosity that developed between Bush and Rubio during the campaign, the senator’s fundraisers are still looking to pick up now-former Bush backers. Peter Brown, a Rubio fundraiser from South Carolina, said he believed it was “unseemly” to pounce on donors less than 48 hours after their candidate dropped out, but that he would begin reaching out to people soon.

“A lot of people had told me prior to this that, as soon as Bush was out, they were planning to go to Rubio,” Brown said. “I will be purposefully going after every Bush supporter that I know.”

Some big names such as Bobbie Kilberg, who had backed both Bush and New Jersey Gov. Chris Christie, did turn immediately to Rubio once Bush dropped out. But after months of Bush and Rubio sparring on the airwaves, campaign trail and debate stage, some donors will likely take time to adjust to supporting their top pick’s onetime protégé.

“Their focus was, ‘How do you clear out the mainstream lane for Jeb Bush?’,” said Ford O’Connell, a Republican strategist who advised U.S. Sen. John McCain’s 2008 presidential campaign. “The person who was hit most by Right to Rise was Rubio.”

Once considered his party’s presumptive nominee, Bush gave a tearful farewell speech Saturday night after placing a distant fourth in the South Carolina primary election. “The people of Iowa and New Hampshire and South Carolina have spoken, and I really respect their opinion, so tonight I am suspending our campaign,” he said.

Bush entered the race last summer with a swell of establishment support and a huge war chest from his super PAC. But the antics and bullying of Trump, combined with voters’ preference for outsider candidates, meant his campaign did not really get off the ground. By the end of it, Bush and his super PAC had spent close to a combined $130 million, and the candidate had just $2.9 million on hand at the end of January, which left some contributors frustrated with the way things turned out.

“I was hoping he’d stay in, I was hoping he’d completely reform the top of his campaign,” said James Wareham, a Bush fundraiser and Washington attorney. “I thought it to be the most incompetently run campaign in the 30 years I’ve been in this arena.”

Wareham said he has not decided whether he will support another candidate, but added that he thought many Bush supporters would eventually line up behind Rubio. “We are not going to nominate ‘Bozo the Bigot,’” Wareham said in a reference to Trump. “The vast majority are deliberating, and those who have decided to do something are going toward Rubio.”

Another option for Bush supporters could be Ohio Gov. John Kasich, who is still in the race. Both Rubio and Kasich have far less cash left than does U.S. Sen. Ted Cruz Texas, and both will need more money if they are going to continue competing in nominating contests through March. Recent election filings showed that Kasich closed January with just $1.5 million and Rubio ended the month with only about $5 million, while Cruz had $13.6 million.

Many have speculated Kasich could be a top vice presidential pick for Rubio should the senator from Florida win the nomination. “People are not going to lose much by giving to a popular governor from Ohio,” Wareham said.

Still, Wareham spent time fundraising for Bush, while contributing the maximum $2,700 to the candidate last summer and more than $40,000 to Right to Rise last year on his own behalf. Other candidates will need to prove they can inspire that kind of loyalty, he said.

“The level of affection for and support for Jeb is intense, and I fear that re-creating that for another candidate has low odds,” Wareham said.

Bush family friend Zeidman said he cast his ballot for Bush Saturday as part of Texas’ early-voting process. In deciding who to support next, he said he wants to avoid wasting his influence again.

“It’s important to see what the Bushes are going to do, and we certainly haven’t been given any indication of what they’re doing yet,” Zeidman said. “Whoever we support will hopefully be the closest to the Bush tradition in viewing the country the same way.”