Jeb Bush, the Republican establishment’s last, best hope, began his 2016 campaign rationally enough, with a painstakingly collated operational blueprint his team called, with NFL swagger, “The Playbook.”

On page after page kept safe in a binder, the playbook laid out a strategy for a race his advisors were certain would be played on Bush’s terms ? an updated, if familiar version of previous Bush family campaigns where cash, organization and a Republican electorate ultimately committed to an electable center-right candidate would prevail.

Story Continued Below

The playbook, hatched by Sally Bradshaw, Mike Murphy and a handful of other Bush confidants in dozens of meetings during the first half of 2015 and described to POLITICO by some of Bush’s closest and most influential supporters, appealed to the Bush family penchant for shock-and-awe strategy. The campaign would commence with six months of fundraising for the “Right to Rise” super PAC and enough muscle to push aside Mitt Romney. There would be a massive, broad-based organizational effort to plant roots in March states at a time when other campaigns were mired in Iowa and New Hampshire. The plan outlined Bush’s positive, future-focused message with an emphasis on his decade-old record of accomplishment as Florida governor.

And it included several pages about the former Florida governor’s case to prosecute against top rivals ? dire political threats such as Wisconsin’s Scott Walker.

The plan roundly underestimated threats: Bradshaw, his closest advisor and long-time defender, for example, told at least one campaign aide that Marco Rubio wouldn’t challenge Bush. Besides, Bradshaw and other top advisers believed, it would be next to impossible for someone with so little experience to beat him. “They thought there was going to be much more reverence and respect for the fact that Jeb Bush, a Bush, was getting into the race,” said one Florida-based supporter, an alumnus of Jeb Bush’s gubernatorial campaigns and former staffer. “When they got Romney to step aside, they figured everyone else would too.”

Most critically, the playbook, people who have read it tell POLITICO, contained nothing about Donald Trump, who would spend the next excruciating year turning Bush into his personal patrician piñata.

“The rules all changed this year. It was all about taking on the establishment,” said a Republican operative close to the Bush family. “When you’re the son and brother of former presidents, the grandson of a U.S. senator, how do you run in a year like this? It is just a year of personality, not message. All of a sudden, there was no path for him. They just kept falling back on his record as governor, which is all he has?and no one gives a shit.”

Interviews with more than two dozen Bush insiders, donors and staff illuminate the plight of an earnest and smart candidate who was tragicomically mismatched to the electorate of his own party and an unforgiving, mean media environment that broadcast his flaws. The entire premise of Bush’s candidacy, these insiders tell POLITICO, was an epic misread of a GOP base hostile to any establishment candidate, especially one with his baggage-weighted last name.

And Bush, known for toughness and hard-work ethic in Tallahassee, just couldn’t project the kind of Reagan-on-‘roids strength demanded by Trump.

“They were just captive to it,” one Washington-based Bush donor said. “And they didn’t adjust very nimbly.”

***

By August, just six weeks after officially launching his campaign, the only thing Jeb Bush’s staff could agree on was the problem: Donald J. Trump.

They’d paid no attention to the New York celebrity’s launch in June, just a day after their own. In early August, well after Trump began to dominate news coverage of the race, they still believed he was a blessing in disguise who would deprive Bush’s lesser-known rivals the media oxygen needed to break through. But as Labor Day neared, Bush found himself on the defensive, peppered daily with questions from reporters asking him to react to Trump’s hardline positions and seemingly outrageous statements on immigration.

But almost immediately, Trump baited Bush into a fight, staking out a position to the far right of the Floridian by calling for an end to automatic citizenship to any baby born in America. He ridiculed Bush’s earlier comment that immigrants who come to the United States illegally do it as an “act of love” for family, and called him unelectable.

Bush fired back, poorly. He went on conservative radio and used the derogatory term “anchor babies” when making the case that he would be a tough enforcer of immigration laws ? opening the floodgates of criticism.

The following week, inside a Mexican restaurant in McAllen, Tex. just a few miles from the U.S.-Mexico border, Bush compounded the problem he was trying to clean up when he explained rather didactically that he was referring to Asians, not Mexicans, who he argued were more guilty of taking advantage of the country’s birthright citizenship provision.

Inside his Miami headquarters, Bush’s senior staffers were coming to the collective realization that the race was veering out of their control.

But that’s where the consensus ended.

David Kochel, the early state strategist initially hired to serve as campaign manager, and senior adviser Trent Wisecup, a protégé of Murphy’s, suggested that Bush challenge Trump to a one-hour, live televised debate on birthright citizenship, perhaps on the O’Reilly Factor. The Fox News host, they argued, supports birthright citizenship, and his show would offer a high-profile platform for Bush to demonstrate his policy knowledge and articulate his more unifying message, bringing the contrast between himself and Trump into sharper relief.

But Bradshaw, the most senior figure in the operation, and campaign manager Danny Diaz couldn’t be convinced it was a risk worth taking, according to high-level campaign staff.

Days later, on Aug. 25, Trump was on stage at a rally in Dubuque when he offered an impression of Bush and characterized him as “low energy,” a critique he’d come up with after the first debate a few weeks earlier.

Bush’s team was stunned, first by the insult but then that it stuck. Kochel and Wisecup raced to respond and saw their already planned event that very same day -- on the anniversary of Hurricane Katrina -- as the perfect opportunity for Bush to respond forcefully and directly to Trump. They envisioned Bush in Pensacola speaking straight to Trump: “You think I’m low energy, why don’t you come down here and talk to these people about how I took charge in a crisis.”

But once again, Bradshaw and Diaz couldn’t be convinced. Trump, they decided, wasn’t in Bush’s “lane” and so the campaign need not worry about responding to him. They went ahead with the event as planned, rolling out a two-minute video telling the story of Bush’s leadership during the hurricanes. The following day, the headlines mainly served to remind readers of another Bush with a less-heralded record on Katrina ? George W. Bush. “One Bush gets praise for his handling of hurricanes” was the Washington Post’s version .

“The Jeb people knew that literally every day when he was governor, he’d walk the steps of the Capitol at a jog pace,” one long-time Bush bundler and confidant said recently. “The building was 30 stories high. You’d hide because you wouldn’t want him to catch you and make you walk the stairs. He’d email you at 5:30 a.m. This was not at all a low-energy guy. It wasn’t true, but it stuck.”

“They got defined as ‘low energy’ by a guy who took an escalator to his own announcement.”

***

Those pivotal days in late August were one of the most critical inflection points for Jeb Bush’s troubled presidential campaign ? the moments when Bradshaw, Kochel, and Diaz might have reconsidered the assumptions made months earlier and redirected their candidate. They didn’t, because that redirection wasn’t part of the playbook.

“You cannot run a political campaign and not have the ability to adapt, to pivot,” one long-time Bush donor who has supported all five of the family’s presidential campaigns. “To sit there and say, ‘We have a book,’ just shows the immaturity."