MIAMI
As Marco Rubio debated whether to run for the United States Senate in 2010, he made a pledge steeped in loyalty and deference: He would never challenge his political mentor, Jeb Bush, if the former Florida governor wanted the job himself.
This time around, Mr. Rubio is not asking for permission.
When Mr. Rubio officially enters the presidential campaign here on Monday, upstaging Mr. Bush in his own backyard, it will signal a decisive, Shakespearean turn in a 15-year relationship so close, personal and enduring that friends describe the two men as almost family.
It is a bond that has stretched from Miami to Washington, punctuated by late-night telephone consultations, fueled by mutual enemies and fixated on reinvigorating conservatism with big ideas, according to dozens of interviews.
The head-on collision of Mr. Bush’s and Mr. Rubio’s presidential aspirations, once viewed as an outlandish prospect in this state, is now consuming their hometown with talk of unchecked ambition and political backstabbing.
But precisely who betrayed whom is a matter of intense debate. Is it the overeager young protégé unwilling to wait his turn? Or the presumptuous teacher, who left government for eight years and sent every signal that he was done with public office, but now wants to return at the highest possible level?
For the hundreds of Florida lawmakers, donors and operatives who know them both, the situation is discussed with funereal dread.
“It’s hard for us to emotionally accept,” said Al Cardenas, a longtime Republican Party leader.
“Nobody thought it would come to this,” said Dominic M. Calabro, president of Florida TaxWatch, an advocacy group.
“I’m not going to lie,” said Ana Navarro, a strategist and fund-raiser. “It gives me a lump in my throat.”
Both men are eager to tamp down the tension. “What do you think,” Mr. Rubio recently asked an associate somewhat sheepishly, “about two friends running for the same office?”
Allies of Mr. Rubio, 43, and Mr. Bush, 62, have rendered an unmistakable verdict: It is an awful idea, upending loyalties and destroying relationships. Many of them, dispensing with the diplomacy that has long surrounded the Bush-Rubio alliance, are starting to lash out.
In an interview at his Miami office, Norman Braman, a fatherlike figure to Mr. Rubio and a major donor to his campaigns, portrayed Mr. Bush as a tired vestige of the past.
“I don’t believe in dynasties,” he said, adding that it was time for the Bush family to “get out of the way” and make room for the fresher-faced Mr. Rubio. “This is not the time to go backward.”
Across town, Mr. Cardenas — who is supporting Mr. Bush and expected Mr. Rubio to graciously sit out the race — turned that generational criticism around. He tartly compared the coming clash to “an uncle and a nephew running for the presidency of the same company.”
Mr. Bush and Mr. Rubio, who live two and a half miles apart, crossed paths in 1998 during Mr. Rubio’s first campaign, at age 26, for city commissioner in West Miami. Mr. Bush, who was running for governor, wrote a $50 campaign check and called to congratulate him the night of his victory.
As Mr. Rubio climbed through the Florida Legislature in the early 2000s, he sought out Mr. Bush, who worked closely with him to defeat the legalization of slot machines in Miami-Dade County and to pass a wide-ranging overhaul of the state’s education system.
“They wanted the same thing,” said Stephen MacNamara, the chief of staff to the Florida House speaker when Mr. Bush was governor. “They agreed on the same conservative ideas and principles.”
Still, the dynamic between Mr. Bush, the governor, and Mr. Rubio, the state lawmaker, was not an equal partnership.
“Jeb was the general,” said Dan Gelber, a Democratic House leader during the time they overlapped in Tallahassee, “and Marco was the smartest lieutenant.”
By the time Mr. Rubio was elected speaker of the Florida House, in 2006, he had cannily positioned himself as the heir to Mr. Bush’s legacy, compiling a book of 100 ideas for Florida’s future and asking the governor to write the introduction.
As Mr. Bush prepared to leave the governor’s office the next year, Mr. Rubio later wrote in his memoir, “I didn’t believe any of the candidates running to succeed him as governor would follow his example of bold leadership.”
So Mr. Rubio anointed himself.
Mr. Bush embraced his eager disciple. When Mr. Rubio was sworn in as speaker, Mr. Bush insisted he hold an elaborate ceremony in which the governor playfully handed him a sword that he said symbolized their shared conservative values.
“It wasn’t just a governor-legislator relationship,” said Nelson Diaz, a lobbyist who worked for Mr. Rubio in the Legislature when Mr. Bush was governor. “It was deeper than that.”
Their alliance grew more urgent with the 2006 election of Gov. Charlie Crist, a moderate who incensed them both by revoking many of Mr. Bush’s personnel appointments and setting out to dismantle much of his agenda.
Over a number of conversations, former aides said, Mr. Rubio and Mr. Bush compared notes on how to hold the line against Mr. Crist and preserve the core of what Mr. Bush had pushed for and Mr. Rubio helped to achieve.
But the imbalance at the center of their relationship came to the fore in the 2010 Senate race, a campaign that simultaneously cemented their ties and laid the seeds of their current rivalry.
Mr. Rubio gave Mr. Bush, three years out of office and contemplating a political comeback, weeks to mull over his own possible bid for the Senate. “If he were to run,” Mr. Rubio wrote in his book, “nobody would challenge him in the primary — certainly not me.”
Mr. Bush declined and worked diligently behind the scenes to nurture Mr. Rubio’s long-shot campaign in the Republican primary against their shared enemy Mr. Crist, who had himself decided to run for the Senate. Mr. Bush introduced Mr. Rubio to his top donors, helped him line up endorsements and dispensed frequent advice from his office at the Biltmore Hotel in Coral Gables.
When Mr. Rubio, initially outgunned and overshadowed by Mr. Crist, weighed dropping out of the campaign in the summer of 2009, it was Mr. Bush who pointedly urged him to stay in the race, according to people told of their conversations. Mr. Crist’s support “is a mile wide and an inch deep,” Mr. Bush told Mr. Rubio, said a person who had been told of the exchange.
Ralph Arza, a Rubio adviser at the time, recalled Mr. Bush’s saying that Mr. Rubio reminded him of himself, boldly challenging a popular sitting governor, as Mr. Bush had done in 1994.
But Mr. Bush did not endorse Mr. Rubio for months, until it became clear that he might win. In the view of Mr. Rubio’s allies, the delay was a political hedge that they say still gnaws at them.
By that point, said Mr. Braman, Mr. Rubio’s close friend, “Marco Rubio didn’t need Jeb Bush.”
Those close to Mr. Bush played down the timing of his endorsement and said he had made no secret of his preference for Mr. Rubio. “Governor Bush was one of his most enthusiastic supporters and probably closest adviser during that race,” Mr. Cardenas said.
Mr. Rubio’s improbable victory that year, in defiance of his party’s leadership and polls that showed him trailing badly for much of the campaign, was a turning point in his career.
And it was, in a way, a turning point in his relationship with Mr. Bush.
“Winning the Senate seat empowered him to realize that he doesn’t need permission,” said Mr. Diaz, the former Rubio aide. “If you want something, go get it. There is no pecking order. There is no line to get in.”
Mr. Bush and Mr. Rubio, who have remained in regular contact even after the Senate campaign, have spoken little in recent months. In December, Mr. Bush called to inform Mr. Rubio that he was officially considering a White House run.
Aides say Mr. Rubio intends to call Mr. Bush before he declares his candidacy next week.
Both sides vow a respectful race, but hurt feelings, and implicit broadsides, are inevitable: Mr. Rubio, nearly 20 years Mr. Bush’s junior, intends to campaign as the youthful symbol of his party’s future, something Mr. Bush is not. “Marco is just younger,” said Mr. Diaz. “It’s a matter of physics.”
It is unlikely to be lost on Mr. Bush that Mr. Rubio has chosen the Freedom Tower, in downtown Miami, as the backdrop for his campaign announcement. The building, which served as a federal processing center for Cuban refugees arriving in Miami in the 1960s and early ’70s, was the source of a rare public dispute between them in 2003.
Mr. Rubio, then the House majority leader, pleaded for the Legislature to set aside $7 million to preserve the historic center. Mr. Bush, a sometimes cold-eyed budget hawk, called the project a “turkey.”
“It’s certainly not a turkey,” Mr. Rubio replied angrily.
Mr. Bush prevailed; the funding was derailed.
On Monday, friends said, when Mr. Rubio addresses his own supporters from the tower’s ornate lobby, his declaration of independence from Mr. Bush will be complete.
