Many of the Republican Party’s most powerful insiders and financiers have begun a behind-the-scenes campaign to draft former Florida governor Jeb Bush into the 2016 presidential race, courting him and his intimates and starting talks on fundraising strategy.

Concerned that the George Washington Bridge traffic scandal has damaged New Jersey Gov. Chris Christie’s political standing and alarmed by the steady rise of Sen. Rand Paul (Ky.), prominent donors, conservative leaders and longtime operatives say they consider Bush the GOP’s brightest hope to win back the White House.

Bush’s advisers insist that he is not actively exploring a candidacy and will not make a decision until at least the end of this year. But over the past few weeks, Bush has traveled the country delivering policy speeches, campaigning for Republicans ahead of the fall midterm elections, honing messages on income inequality and foreign policy, and cultivating ties with wealthy benefactors — all signals that he is considering a run.

Many if not most of 2012 GOP nominee Mitt Romney’s major donors are reaching out to Bush and his confidants with phone calls, e-mails and invitations to meet, according to interviews with 30 senior Republicans. One bundler estimated that the “vast majority” of Romney’s top 100 donors would back Bush in a competitive nomination fight.

“He’s the most desired candidate out there,” said another bundler, Brian Ballard, who sat on the national finance committees for Romney in 2012 and John McCain in 2008. “Everybody that I know is excited about it.”

But Bush, 61, would have serious vulnerabilities as a candidate. Out of public office for seven years, he has struggled in some appearances and has had difficulty navigating the Republican Party’s fault lines on immigration and other issues. A Bush candidacy also would test whether the nation still has a hangover from the George W. Bush administration.

On Thursday night, Bush was feted here at a VIP dinner held by Sheldon Adelson inside the billionaire casino magnate’s airplane hangar. When one donor told Bush, “I hope you run for president in 2016,” the crowd of about 60 guests burst into applause, said a donor in attendance.

Bush also met privately with Adelson. One person with knowledge of the conversation said that the former governor was “very laid back and comfortable” and that they did not discuss the 2016 campaign.

Bush has been nurturing donor relationships for years. Earlier this month, he headlined a fundraiser for Virginia Senate candidate Ed Gillespie at former ambassador Al Hoffman’s home in North Palm Beach, Fla. Private-equity manager Lewis M. Eisenberg and former ambassador Ned Siegel were among the heavy hitters in attendance.

And in July, investor Scott Kapnick threw a book party for Bush at his Manhattan apartment. About 100 leading GOP donors showed up.

Such events are a reminder that Bush, the son and brother of past presidents, could quickly activate a large national fundraising network if he runs.

He would enter a wide-open contest for the GOP nomination with other advantages, as well: deep ties to his party’s establishment and evangelical wings, and a reputation as a reform-minded policy wonk. Fluent in Spanish, Bush has credibility within the Hispanic community that could help broaden his coalition. He also has the gravitas many Republicans say is required to compete with former secretary of state Hillary Rodham Clinton, the Democrats’ leading potential contender.

“Jeb has the capacity to bring the party together,” said Fred Malek, a top Republican official who said he has been in regular contact with Bush.

For now, Bush’s 2016 deliberations are limited to casual e-mails and chats with Sally Bradshaw, his longtime political counselor in Florida, and strategist Mike Murphy. He also is in contact with fundraiser Jack Oliver.

Bush’s small travel entourage sometimes includes Josh Venable, a vice president at Bush’s education foundation who serves on the side as Bush’s liaison with big donors, and Kristy Campbell, a former Romney aide who is Bush’s spokeswoman.

Bush often writes gracious thank-you notes to those urging him to run but takes care never to indicate whether he is moving toward a campaign.

“He is not in the middle of a formal process,” Bradshaw said. “He is methodical, he is thoughtful, and he’ll make a decision by the end of the year or the first quarter of next year.”

Bush declined a request for an interview.

People close to him said a major concern about running is navigating today’s messy spectacle of Twitter wars and super PAC attacks. In January, Bush said, “The decision will be based on ‘Can I do it joyfully,’ because I think we need to have candidates lift our spirits.”

This year, Bush has campaigned for New Mexico Gov. Susana Martinez, Nevada Gov. Brian Sandoval, Sen. Lamar Alexander (Tenn.) and other Republicans. He also cut a television ad supporting David Jolly (R), who recently won a special congressional election in Florida.

In early May, Bush plans to headline a fundraiser in Jacksonville, Fla., featuring many of his long-standing patrons, to support South Carolina Gov. Nikki Haley (R).

Bush takes pains not to be seen contacting key Republicans from early-primary states, but in October, he asked a staff member for the cellphone number of Sen. Kelly Ayotte (N.H.). He called Ayotte to commend her for standing up to their party’s conservative bloc during the federal government shutdown, people familiar with the conversation said.

Last month, Bush spoke in Southern California about income inequality, arguing that the problem is a lack of mobility and not the gulf between rich and poor. “This nation is experiencing a crisis of opportunity,” he said, according to his prepared remarks.

Mark DeMoss, a former adviser to Romney who is well connected with evangelicals, said that he would help Bush — but that if Bush doesn’t run, he will sit out the 2016 campaign.

“I think he is a talented, credible, thinking leader,” DeMoss said. “The question is, how much appetite is there in the Republican Party and in the general electorate for that?”

In the past, Bush has decided against seeking national office. His wife, Columba, who was born in Mexico, shies away from the limelight.

Bush ran his last campaign in 2002, and during last year’s rollout of his book, “Immigration Wars,” his inconsistent position on a path to legalization revealed that he is politically rusty.

“It’d be a little odd to nominate someone who was last in office in 2006, who hasn’t been politically involved at all, in any significant way, in the Obama years,” said William Kristol, editor of the Weekly Standard, a conservative magazine.

Bush’s vocal support for immigration reform and Common Core education standards — lightning-rod issues for tea party activists — could dog him in the GOP primaries.

He has taken small steps to assert his conservative bona fides. Last spring, Bush hosted a dozen high-profile conservatives, including writers for the Wall Street Journal’s editorial page, at a dinner at Washington’s Willard InterContinental Hotel, where he defended Common Core standards.

And unlike Christie and Ohio Gov. John Kasich — two Republicans who agreed to expand Medicaid under President Obama’s health-care law — Bush has spoken out against doing so.

In any campaign, Bush would have to grapple with the legacy of his brother George W. Bush and his unpopular wars. A recent Washington Post-ABC News poll found that almost half of all Americans surveyed say they “definitely would not” vote for Jeb Bush for president.

“The ‘Bush fatigue’ question is always there,” said former Mississippi governor Haley Barbour (R). “If his name was Jeb Brown instead of Jeb Bush, he’d be the front-runner.”

Bush has not spoken much about foreign affairs, but at Thursday’s speech to the Republican Jewish Coalition, he articulated a muscular if generic conservative foreign policy, participants said.

Bush is in regular touch with foreign policy thinkers such as former secretary of state Henry Kissinger, who said in an interview that he would be “delighted” if Bush ran — although Kissinger said he also likes Christie.

“He would be outstanding,” Kissinger said of Bush. “He is someone who is experienced, moderate and thoughtful.”

Romney invited Bush to attend his upcoming June donor policy conclave in Park City, Utah. Bush declined because of a scheduling conflict, according to an aide. Christie and Paul were at Romney’s summit last year.

Although Christie intended to try to round up early support from Romney’s donor base, most of those bundlers have deeper roots with Bush. Former ambassador Mel Sembler, one of Romney’s national finance co-chairmen, has known Bush for decades. “He is a quality candidate, an excellent leader,” Sembler said.

Strategists for other prospective candidates said they are growing nervous about Bush and fear that he could lock up the donor class. “He would take some of the oxygen out of the air,” said David Carney, an ally of Texas Gov. Rick Perry (R).

A Bush candidacy also would pose a threat to Sen. Marco Rubio (Fla.), whose donor and political circles overlap with those of the former governor. Bush blessed Rubio’s rise to the state House speakership, but their affiliation has since faded. Florida Republicans familiar with Rubio’s thinking said he is moving forward with a campaign, betting that Bush will not run.

Former New Jersey governor Thomas H. Kean, who mentored a young Christie, acknowledged that Bush could block Christie’s path as the establishment favorite.

“The Bush family has an enormous number of friends who would be liable to go back to a place where they have been before,” Kean said.

Costa reported from Washington.