Dozens of the Republican Party’s leading presidential donors and fundraisers have begun privately discussing how to clear the field for a single establishment candidate to carry the party’s banner in 2016, fearing that a prolonged primary would bolster Hillary Rodham Clinton, the likely Democratic candidate.

The conversations, described in interviews with a variety of the Republican Party’s most sought-after donors, are centered on the three potential candidates who have the largest existing base of major contributors and overlapping ties to the top tier of those who are uncommitted: Gov. Chris Christie of New Jersey, former Gov. Jeb Bush of Florida and Mitt Romney.

All three are believed to be capable of raising the roughly $80 million in candidate and "super PAC" money that many Republican strategists and donors now believe will be required to win their party’s nomination.

But the reality of all three candidates vying for support has dismayed the party’s top donors and "bundlers," the volunteers who solicit checks from networks of friends and business associates. They fear being split into competing camps and raising hundreds of millions of dollars for a bloody primary that will injure the party’s eventual nominee — or pave the way for a second-tier candidate without enough mainstream appeal to win the general election.

"If you are philosophically a center-right donor, I think you have an interest in clearing the field," said Bobbie Kilberg, a top Republican fundraiser in Virginia with ties to Romney and the Bush family. "I think that’s important because there is clearly going to be a competition of philosophies for who is going to be the presidential nominee. And I firmly believe that person has to be from the center-right."

But talk of an establishment coronation is likely to incur the wrath of party activists and outside groups seeking a more conservative nominee.

For the first time in decades, the Republican Party is facing a wide-open primary with up to a dozen serious candidates representing virtually every branch of the party. Republican leaders, hoping to minimize damage to their eventual standard-bearer, have already sought to compress the formal primary season and reduce the number of candidate debates.

With the midterms over, Christie and Bush have begun pushing top bundlers to commit to them in advance should they announce a White House bid, according to several donors, putting intense pressure on the corps of contributors who helped Romney and the Republican Party raise a billion dollars for the 2012 campaign. Those requests have intensified the discussion in some circles about whether to coalesce behind a single candidate early or, alternatively, delay it until after the early Republican debates next summer.

"What the donors are looking at is, how do we find someone we are confident can win and not get involved in 2015 with people just throwing money around," said Ray Washburne, the finance chairman of the Republican National Committee, who has met with most in the likely presidential field.

Many leading donors, like Woody Johnson, the billionaire New York Jets owner, who helped lead Romney’s Northeast fundraising efforts in 2012, have relationships with both Bush and Christie, but would prefer to wait until Romney makes a decision, according to people who have discussed the matter with Johnson. Johnson hosted both Christie and Romney at a Jets game last week.

The fear of a bloody primary extends even to the ranks of the ultra-wealthy donors whose seven-figure largess to super PACs helped prolong the Republican nomination battle in 2012, forcing Romney into pitched battles for late-voting states like Michigan.

Foster Friess, who donated $2.1 million to a super PAC backing Rick Santorum in 2012, said he was committed to helping Santorum again. But he has discussed with other donors the need to encourage candidates to avoid overly personal attacks.

"I think this time the candidates are not going to be quite as divisive in the primary season," Friess said.

Sheldon G. Adelson, the casino mogul whose family provided $20 million to a super PAC backing Newt Gingrich in 2012, is increasingly wary of writing checks to consultant-run outside groups, according to his political advisers.

"We are evaluating all options, and we may fundamentally change how we engage in the process while staying true to our principles," said Andy Abboud, one of Adelson’s lieutenants.

Adelson, who is based in Las Vegas, is engaged in discussions with his small circle about how to take his political spending in-house and is considering setting up his own super PAC to intervene in congressional and presidential races. And Adelson, a major donor to pro-Israel groups and someone with moderate views on social issues, is inclined to be more cautious when engaging in the Republican primary.

"He’s very focused on picking someone who can win," said a Republican strategist involved in the discussions, who spoke on the condition of anonymity because Adelson was not yet ready to announce his plans. "He wants to ensure whatever candidate he gets behind reflects that philosophy and can win the general election."

Many donors said they believed that Romney was likely to wait until late summer to decide whether to enter the race, while Christie could make a decision much sooner. That could leave elite bundlers — already jockeying for status and rank within the campaigns’ likely finance operations — in an awkward position if Romney does not run.

"When you get that call" to commit to Bush or Christie, said one prominent Republican fundraiser, "the answer to that question is yes."

The fundraiser, who spoke on the condition of anonymity to preserve his relationships with all three men, added: "Anything else and you’re on the B team. You’re on the second list. People that like to do this want to be on the A team."

Some donors said they believed it was now inevitable that the primary would feature more than one establishment candidate along with several from the Tea Party wing. In that case, the donors said, they would probably seek to avoid committing substantial resources or coalescing behind any one candidate until later next year.

The discussions are unfolding against a burst of 2016-related activity in recent weeks, with potential candidates like Sen. Rand Paul of Kentucky and Gov. Rick Perry of Texas organizing private conferences of potential staff members and donors.

Perry’s ability to continue tapping into the deep well of wealthy Texas donors would be tested by Bush’s entry into the race. Perry may also find it harder to raise money when he leaves behind the Texas governor’s office — and the thousands of political appointments it controls around the state — in January.

Paul has avidly courted establishment donors and bundlers across the country in recent months, generating more interest than firm commitments to his likely 2016 campaign. While he has added political staff for a potential White House bid, including the former finance director for Mitch McConnell, the incoming Senate majority leader, several donors said they did not believe there was an obvious candidate to lead Paul’s fundraising operation.

"Can’t have a finance chair for something that doesn’t exist," Doug Stafford, Paul’s top political aide, said in an email. "We have a large and expanding finance team, both professionals, bundlers and volunteers. Announcements on who they are and what positions they hold would be premature at this point."

Nicholas Confessore, New York Times