The South Carolina primary is poised to dramatically alter the Republican nomination contest, winnowing and clarifying the largest and most rambunctious GOP field in decades.

Many in the party’s upper echelons have grown impatient with their splintered field of center-right, mainstream contenders and say they intend to put pressure on whichever candidate falls short of third place on Saturday night to quit.


"South Carolina will reshape the race," said Scott Reed, the chief political strategist at the U.S. Chamber of Commerce. “Only the top three finishers will have a true narrative to continue down the road."

South Carolina has a long history of defining the course of Republican nomination fight. George W. Bush’s win over John McCain there marked a turning point in the bitter 2000 contest, as did Ronald Reagan's 1980 win over George H.W. Bush. “South Carolina has always been pivotal,” McCain said in an interview on Friday, recalling his difficult defeat.

Under the most pressure this year is another Bush. After disappointing showings in Iowa and New Hampshire, Jeb Bush has staked his campaign on South Carolina, dispatching his brother and mother, former First Lady Barbara Bush, to jog voters’ fond memories of Bushes past. Despite the family’s efforts, however, most polls in recent days have shown Bush hovering in single digits, far behind rival Marco Rubio.

Barring a surprise showing, many believe Bush’s best hope is a fourth-place finish just behind Rubio – an outcome that could justify staying in at least through Tuesday’s vote in Nevada.

“It is clear there are three tickets coming out of South Carolina,” said Phil Cox, a former Republican Governors Association executive director. “Whether there is a fourth ticket will depend on the gap between third and fourth place. It will become very difficult for anything beyond a close fourth-place finish to be able to keep putting gas in the tank and attract the kind of media attention necessary to keep going.”

The former governor was dealt a serious blow this week when popular South Carolina Gov. Nikki Haley, a rising star in the party, announced her support for Rubio. Shortly before the endorsement was revealed, Haley called Bush to tell him of her decision.

In recent days, Bush and his team have been insisting to top supporters that he will be going on – regardless of what happens on Saturday. The former governor spent part of the week reaching out to top donors and asking them for fundraising help, in some cases asking for donations of up to six figures. In those conversations, sources briefed on the talks said, Bush said that he planned to compete in the Nevada caucuses on Tuesday.

Bush’s top advisers have been calling top Republican operatives in Washington to brief them on their standing – and to reiterate that the former governor will push on to Nevada. On Friday, his team released a travel schedule that included Nevada stops on Sunday and Monday.

If Bush bows out, a large and wealthy set of establishment-minded donors will be free to throw their support elsewhere. The former governor has tapped into his family’s loyal political network to amass over $120 million in contributions, and many Republicans say they think Rubio would be able to secure the backing of most of those donors, many of whom are eager for the party to unite behind a single contender to combat Trump and Cruz.

“The donor community is desperate to get someone out to focus on stopping Trump,” said former House Speaker Newt Gingrich, who won the South Carolina primary in 2012.

Rubio backers also hope that a smaller GOP field will bring party veteran Mitt Romney off the sidelines with an endorsement. Those close to Romney say he’s anxious to defeat Trump and Cruz – and that a Bush exit could nudge him closer to blessing Rubio.

Other power-brokers, though, are likely to remain neutral. Las Vegas casino mogul Sheldon Adelson, one of the Republican Party’s biggest donors, had long been seen as a potential Rubio endorser, but he has yet to side with the Florida senator – or any candidate in the race, for that matter. An Adelson adviser said the billionaire was now unlikely to get behind anyone until the party selects a nominee.

Another establishment candidate, John Kasich, is expected to fare poorly in South Carolina but is virtually certain to continue on no matter his showing on Saturday. Kasich is focusing on Michigan’s March 8 contest and his home state of Ohio, which votes a week later. Kasich, who has staked out moderate turf, is also eying the northeast. A pro-Kasich super PAC, New Day for America, is expected to begin placing TV commercial reservations in Vermont and Massachusetts, which hold their primaries on March 1, according to a source familiar with the group’s planning.

South Carolina may transform the contest in other ways. Some in the Republican establishment worry that, following his runaway performance in New Hampshire, a lopsided Trump win would create an unmistakable sense of momentum heading into Nevada and the Super Tuesday states that vote on March 1. Most South Carolina surveys show Trump holding leads of anywhere from 15 to 20 percent.

“I think it would make him very difficult to stop, especially if he wins by a large margin, which is what the polls are indicating,” said McCain, the 2008 GOP nominee. “To state the obvious, if he wins, it’s significant.”

McCain marveled at the state of the race, describing it as divisive, deeply confusing and, worse, potentially damaging to the party. He said that the anger coursing through the party was permeating races all over the country – including his own. McCain is currently trying to beat back a primary challenge from a conservative insurgent.

Whatever transpires, McCain said he’d become concerned about the party’s ability to unite following a primary contest that he labeled “coarse.”

“I haven’t seen a situation like this in my political life,” he said. “It’s hard to predict what’s going on.”